Stomach - Foveolar cells are mucus-producing cells, which cover the inside of the stomach, protecting it from the corrosive nature of gastric acid. The mucus produced by these cells is extremely important, as it prevents the stomach from digesting itself.
Duodenum - Brunner's glands (or duodenal glands) are compound tubular submucosal glands present in the duodenum. The main function of these glands is to produce a mucus-rich alkaline secretion (containing bicarbonate) in order to: protect the duodenum from the acidic content of chyme (which is introduced into the duodenum from the stomach); provide an alkaline condition for the intestinal enzymes to be active, thus enabling absorption to take place and lubricate the intestinal walls.
Large intestine - Goblet cells reside throughout the length of the small and large intestine and are responsible for the production and maintenance of the protective mucus blanket by synthesizing and secreting high-molecular-weight glycoproteins, known as mucins. 

Malpighian tubules are the excretory organs in all insects. The tubules often occur in two’s or multiples of two. As insects belong to the phylum Arthropoda, the organism must be placed under it. 

The excretory organs of grasshopper are the malpighian tubules which are coiled about in the haemocoel and open into the anterior end of the hindgut. The malpighian tubules have a wall of a single layer of cells with striated inner border. Their free ends are completely closed. In the majority of Arthropods, Malpighian tubules are the excretory organs. So, the correct option is 'Malpighian tubule'.

On the basis of development, there three types of kidneys as pronephric kidney, mesonephric kidney and the metanephric kidney.

The excretory product of freshwater fishes is 'ammonia'.

• Amphibians have mesonephric type of kidneys which are primitive compared to metanephric kidneys. 
• Mesonephric kidneys do not have nephrons but their nephrons do not contain a loop of Henle.

Nephridia is the earthworm's excretory organ. Earthworms are called septal, integumentary, and pharyngeal nephridia in three kinds of nephridial structures. These three nephridial structures are present in various body positions and differ in structures as well. Septal and pharyngeal nephridia are both enteronephric, i.e. they expel nitrogen products to the gut. Integumentary nephridia is exonephric, i.e. products of nitrogen waste are discharged outside straigh

Amphioxus or Branchiostoma is a peculiar chordate animal, which does not have excretory organs in the form of mesodermal kidneys but are in the form of protonephridia. They are similar to protonephridia of flat worms or polychaete, annelids and they are ectodermal in origin. In Amphioxus there are 90 to 100 pairs of protonephridia present segmentally on dorso-lateral pharyngeal wall one above each gill slit on either side. Simply, they are ciliated, thin walled, closed ectodermal tubules like structures.

The original nephrostomes remain in the adult frog on the ventral face of the kidney as ciliated peritoneal funnels. These convey coelomic fluids directly into the blood sinuses of the kidney. They are regarded as accessory excretory structures.

The excretory organs of earthworm are coiled tubular structures, known as nephridia. A nephridium consists of a ciliated nephridial canal, that opens into the coelom by nephrostome and to the exterior or in the gut by nephridiopore. The walls of nephridia are glandular and richly supplied with blood vessels, they extract solutes and water from the blood by ultra filtration, and discharge the filtrate into the nephridial canal. 

In most of the invertebrates, the excretory structures are simple tubular forms whereas vertebrates have complex tubular organs called kidneys. Shark is a vertebrate and has kidneys as excretory structures.
Protonephridia or flame cells are the excretory structures in Platyhelminthes (Flatworms, e.g., Planaria), rotifers, some annelids and the cephalochordate Amphioxus. Protonephridia are primarily concerned with ionic and fluid volume regulation, i.e., osmoregulation.
Nephridia are the tubular excretory structures of earthworms and other annelids like Leech. Nephridia help to remove nitrogenous wastes and maintain a fluid and ionic balance.
Malpighian tubules are the excretory structures of most of the insects including cockroaches. Malpighian tubules help in the removal of nitrogenous wastes and osmoregulation.

Nephridial organs, or nephridia, are excretory structures that evolved in many invertebrates, including flatworms, nemerteans, rotifers, annelids, mollusks, and lancelets. Each nephridial organ consists of simple or branching tubes that typically open to the outside of the body through excretory pores, called nephridiopores. Two types of nephridial organs are protonephridia and metanephridia. The excretory system of insects and spiders consists of several hundred Malpighian tubules. Malpighian tubules are slender extensions of the gut wall. Their blind ends lie in the hemocoel (blood cavity) and are bathed in hemolymph. The mammalian urinary system consists of the kidneys, the urinary bladder, and associated ducts. Each kidney has more than 1 million functional units called nephrons. A nephron consists of a cuplike Bowmans capsule connected to a long, partially coiled renal tubule.
In option A typhlosole is an intestinal fold for absorption but contractile vacuole is meant for osmoregulation. In option C antennae of cockroach are sensory but clitellum of earth worm forms cocoon. In option D tube feet of starfish are meant for locomotion and not related to other structures mentioned which have a role in digestion of food.

'Green Gland' is one of the pair of excretory organs in each side of the head region of decapod crustaceans, emptying at the base of the antennae. Prawns have green glands for excretion.

Solenocytes are a type of long, narrow, flagellated cell that functions in excretion of nitrogenous wastes and occurs in a variety of organisms, including certain annelids and molluscs.

Wolffian duct is also called as archinephric duct, is a pair of tubes that carry urine from primitive or embryonic kidneys to the exterior or to a primitive bladder. 

Various animals of animal kingdom presents a variety of excretory structures. In most of the invertebrates, these structures are simple tubular forms. Protonephridia or flame cells are the excretory structures in Platyhelminthes (Flatworms, e.g., Planaria), rotifers, some annelids and the cephalochordate Amphioxus. Protonephridia are primarily concerned with ionic and fluid volume regulation, i.e., osmoregulation. Nephridia are the tubular excretory structures of earthworms and other annelids. Nephridia help to remove nitrogenous wastes and maintain a fluid and ionic balance. Malpighian tubules are the excretory structures of most of the insects including cockroaches. Malpighian tubules help in the removal of nitrogenous wastes and osmoregulation. Antennal glands or green glands perform the excretory function in crustaceans like prawns. Vertebrates have complex tubular organs called kidneys as primary excretory organ. Towards the centre of the inner concave surface of the kidney is a notch called hilum through which ureter, blood vessels and nerves enter. Inner to the hilum is a broad funnel shaped space called the renal pelvis with projections called calyces. The outer layer of kidney is a tough capsule. Inside the kidney, there are two zones, an outer cortex and an inner medulla. The medulla is divided into a few conical masses (medullary pyramids) projecting into the calyces (sing.: calyx). The cortex extends in between the medullary pyramids as renal columns called Columns of Bertini.

Mammals like humans and rabbit, many terrestrial amphibians and marine fishes mainly excrete urea and are called ureotelic animals. Ammonia produced by metabolism is converted into urea in the liver of these animals and released into the blood, which is filtered and excreted out by the kidneys. Some amount of urea may be retained in the kidney matrix of some of these animals to maintain a desired osmolarity.

Hepatic caecum is found in grasshopper, which secretes enzymes into the stomach here they assist in the digestive process.
The food in the grasshopper, after entering into oesophagus, enters into the crop. here, the masticated food is temporary stored.
The hemolymph is equivalent to blood of grasshopper
Egestion is the process of discharging undigested or waste material from a cell of organ.
Therefore, the correct answer is option A.

The ductus deferens, also known as the vas deferens, is a tiny muscular tube in the male reproductive system that carries sperm from the epididymis to the ejaculatory duct. 

In the substrate eaters like Balanoglossus, the excretory organ is glomerulus or proboscis gland lying in front of the central sinus and projecting into the proboscis coelom.

Green glands are excretory organs in crustaceans. The excretory organ in annelids is nephridia. The column of bertini is an extension of renal cortex between the renal pyramids.

The metanephric kidneys are a paired compact organ whose functional units are nephrons. The nephrons filter initial urine from the blood, reabsorbing water and nutrients, and secrete wastes, producing the final urine, which is expelled. In adult Frog, The kidney is Metanephros.

Planarians are one of the types of flatworms belonging to the class Turbellaria. The excretory organs of planarians are flame cells. The flame cells work like a kidney and remove excretory wastes from the body.

Sea gulls are marine birds belonging to the family Laridae. They drink salt water as a result to maintain their osmotic balance they excrete salts through nasal gland or salt gland present in the nostrils and assist kidney in maintaining electrolyte balance.

Amoeba is a fresh water unicellular organism. In amoeba the excretory waste is ammonia. The excretory waste present in the cytoplasm is collected by contractile vacuole then this excretory waste i.e NH$ _3$ is excreted through plasma membrane by diffusion.

Hydra is a freshwater sessile organism belonging to the phylum Cnidaria and class Hydrozoa. They are found in lakes, pond, and stream. Hydra is ammonotelic i.e they secrete ammonia as chief excretory nitrogenous waste. In hydra specialized excretory organs are absent hence in hydra, wastes of food digestion and nitrogenous wastes are removed from mouth and body wall.

The excretory system of frog consists of a pair of kidney, ureters, urinary bladder and cloaca. On the ventral surface of the kidney in the frog, there are ciliated funnels present called as nephrostome. The nephrostome is internally lined with cilia, its function is to push water, metabolic wastes and other substances into metanephridium (Kidney).

The frogs which are highly aquatic belongs to the genus xenopus. They are usually found in lakes, rivers, swamps. The xenopus excretes ammonia as nitrogenous waste hence ammonotelic.

For many chordates, the urinary system is a critical component of the excretory system. It is made up of organs such as the kidneys and bladder, structures such as a urethra or cloaca, and even arteries such as the aorta. The urinary system is responsible for both creating and excreting urine, which it does to regulate the amount of water and solutes within the body. Amazingly enough, the urinary system also works closely with hormones in your body that signal when you start to become dehydrated or when there is too much fluid in your body.

So, the correct option is 'All chordates'.

In decapod crustaceans, the excretory organs are known as antennary glands or green glands. These glands are opaque-white, pea seed sized structures, enclosed in the coxa of each second antenna. These glands play an important role in the process of excretion.

Earthworms (annelids) have slightly more evolved excretory structures called nephridia. A pair of nephridia is present on each segment of the earthworm. Malpighian tubules are found lining the gut of some species of arthropods, such as the bee. They are usually found in pairs and the number of tubules varies with the species of insect.

Green glands are excretory organs of some arthropods like crustaceans. They are also called antennal glands because these glands are located near the base of larger antennae. Each gland has three parts end sac, labyrinth and bladder. The labyrinth is the proper excretory gland. Hence green glands help in excretion.

Green glands are excretory organs of some arthropods like crustaceans.  For example, prawns, crayfishes, lobsters etc. They are also called antennal glands because these glands are located near the base of larger antennae. Each gland has three parts end sac, labyrinth and bladder. The labyrinth is the proper excretory gland. Hence antennal gland functions as the excretory organ in prawn.

Earthworms (annelids) have slightly more evolved excretory structures called nephridia. A pair of nephridia is present on each segment of the earthworm. Excretion occurs through a pore called the nephridiopore. Malpighian tubules are found lining the gut of some species of arthropods, such as the bee. They are usually found in pairs and the number of tubules varies with the species of insect.

Hepatopancreas is not an excretory organ of vertebrates. It is a glandular excretory organ present in many invertebrates like arthropods and molluscs. It shows functions similar to liver and pancreas of vertebrates.

Salamander belongs to the phylum Chordata and class amphibia. Just like humans, the salamander has two kidneys which excrete urea as the nitrogenous waste product. Two kidneys are extremely important in excreting nitrogenous waste, and the urinary bladder stores waste in the form of urea before it is released into the environment.

Hydra is sessile and cylindrical in shape belonging to the phylum Cnidaria and class Hydrozoa. It has no specialized excretory organs hence excretion in hydra occurs by diffusion through the general body surface.

Green glands are excretory organs of crustaceans. For example, prawn. They are also called antennal glands because these glands are located near the base of larger antennae. Each gland has three parts end sac, labyrinth and bladder. The labyrinth is the proper excretory gland. Hence green glands help in excretion.

Green glands are excretory organs of crustaceans. They are also called antennal glands because these glands are located near the base of larger antennae. Each gland has three parts end sac, labyrinth and bladder. The labyrinth is the proper excretory gland.

Rotifers are microscopic aquatic animals belonging to phylum rotifera. They eat dead bacteria, algae and protozoans. The excretory structures of rotifers are Flame cells. The flame cells function like a kidney, removing nitrogenous waste.

Birds excrete nitrogenous wastes as uric acid in the form of a pellet or paste with a minimum loss of water. Therefore they are called uricotelic animals. 

(A) The process of excreting ammonia is Ammonotelism. Many bony fishes, aquatic amphibians and aquatic insects are ammonotelic. 

Malpighian tubules are excretory structures in most insects, including cockroaches, but in crustaceans such as prawns, green glands conduct excretory functions, whereas all other statements are true.

Crop milk is a secretion from the lining of the crop of parent birds that is regurgitated to young birds. They are found among all pigeons and doves, where they are referred to as pigeon milk. Crop milk is also produced by flamingos and some penguins.

Bioluminescence is the production and emission of light by a living organism. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria and terrestrial invertebrates such as fireflies. 

Gymnophiona, also called apoda, is one of the three major extant orders of the class amphibia. Its members are known as caecilians. Their skin is smooth but some species have colourful skins. Inside the skin are calcite scales. Because of these scales, the caecilians were once thought to be related to the fossil Stegocephalia.

The renal gland is a relatively wide tube opening from a sac (the pericardium) surrounding the heart, at one end, and to the mantle cavity (effectively to the exterior) at the other. The anatomical form of the renal gland varies from one class of molluscs to another.

The Bowman's capsule and the glomerulus together constitute the malpighian corpuscle (pygmalion corpuscle or renal corpuscle). The malphigian corpuscles were first described by Morcello Malpighi in the year 1966.

Birds and reptiles urinate in a way to conserve their water. Unlike mammals, which excrete waste fluid as urine and solid waste as faeces, birds and reptiles mix both liquid waste and solid waste into the semi-solid paste (nitrogen containing waste) formed from the breakdown of proteins. Hence snakes, crocodiles, birds and most lizards lack a urinary bladder.

Bright's disease is a classification for nephritis, a kidney condition. Nephritis is caused by inflammation of part of the kidneys, usually either the glomeruli or the spaces in between the renal tubules. Symptoms most commonly associated with Bright's disease are intense pain on either or both sides of the lower back along with a fever and nausea. Cloudy, dark, or bloody urine containing blood plasma proteins is also a hallmark sign of kidney problems. 

The excretory system of earthworm contains a pair of nephridia in every segment, except for the first three and the last ones. The three types of nephridia are: integumentary, septal, and pharyngeal. The integumentary nephridia lie attached to the inner side of the body wall in all segments except the first two. The septal nephridia are attached to both sides of the septa behind the 15th segment. The pharyngeal nephridia are attached to fourth, fifth and sixth segments.

In many higher crustaceans the excretory glands are located in the head. They are called antennal glands or maxillary glands, depending on whether they open at the base of the antennae or at the maxillae.

Chloragogen cells in annelids function similarly to the liver in vertebrates. The cells store glycogen and neutralize toxins, are yellowish in colour due to the presence of yellow granules, called as chloragosomes and are present in coelomic fluid of some annelids.

A flame cell is a specialized excretory cell, found in the simplest freshwater invertebrates, including flatworms, rotifers and nemerteans. These are the simplest animals to have a dedicated excretory system. Flame cells function like a kidney, removing waste materials.

The loop of Henle is incompletely developed or absent in many nephrons of the bird kidney. Hence, the concentrating capacity of the bird kidney is considerably less than that of the mammal. 

The term pelage is used to refer to the body hair of an animal as a complete coat. Its principal function is thermoregulation, it maintains a layer of dry air next to the skin and repels water, thus providing thermal insulation.

The excretory organ of cockroach is the Malpighian tubules. It is found at the junction of the midgut and hindgut and are about 150 in number. 

A kidney stone is a solid cluster made up of tiny crystals. 

Mesonephric kidney- Develop from middle part (mesonephros) of nephrotome plate and remaining part of nephrotome is destroyed. Only Bowman's capsule is found in nephrons, while remaining part is simple tubular, e.g., most of the fishes and adult amphibians.

Porifera (sponges), Platyhelminthes (flatworms) and Cnidaria (Hydra) do not have a well-developed digestive system. They have 'blind-sac' body plan, with an opening that serves as both the mouth and the anus, and a gastrovascular cavity where digestion takes place.

Birds and reptiles have uric acid as their nitrogenous waste. 

(A) Buccal cavity: 1-3

(A) Deglutition is the process of swallowing the masticated food.

Lactobacillus delbrueckii is a beneficial bacteria found in the digestive tract. The proper balance of gut flora helps to keep your intestinal walls strong and bad bacteria at bay and can reduce the risk of chronic disease. which are highly adapted to growing on lactose and converting it into lactic acid.

Alimentary canal is also called as digestive tract. It starts in the mouth followed by buccal cavity and ends at the anus. The digestion starts in the anterior cavity called buccal cavity. Teeth are embedded in a socket of mandible (lower jaw) and maxilla (upper jaw). These sockets are called as tooth sockets. Human shows both diphyodont and monophyodont types of dentition. In diphyodont dentition, there are 2 sets of teeth, namely deciduous and permanent set. In monophyodont dentition, there is only 1 set of teeth. In humans, molar teeth show monophyodont dentition and rest teeth show diphyodont dentition. Pharynx is part of both digestive and respiratory system. Pharynx opens into oesophagus in digestive system and larynx in respiratory system. 

Esophagus, colon and rectum are studied with the T.S. of the gut. They are all a part of the digestive system where is wearing is a part of the digestive as well as the respiratory system and it is not studied along with them.

It begins in the stomach by pepsin which breaks down the peptide bind and makes protein smaller for easier digestion. Trypsin and chymotrypsin are also enzymes that are created by the pancreas and will cut down proteins into small peptides. 

All of these choices are a part of your digestive system. Your digestive system has many other associated organs including the small intestine, large intestine, and liver. The stomach is an area of food digestion. The pancreas releases hormones, that affect the digestive process. The rectum is the last place you store you food before the process of elimination (pooping).

The pharynx connects the mouth to an area in your throat with a flap. The flap is the epiglottis. The flap moves to one side for food and the other side as you breathe. The branching point leads to the larynx or the esophagus.

The alimentary canal of grasshopper is divided into three main portions as

• Foregut
  
• Midgut
  
• Hindgut
  

In the stomach, the enzyme pepsin breaks protein into smaller pieces called polypeptides. For proper functioning of pepsin, acidic pH is necessary; a pH of 2 is optimum for pepsin function. Antacids neutralize the normal stomach acid pH and brings it upto 6 to 7. As pH rises above 4, pepsin activity decreases or stops. That is why when a person takes too much antacid the pH of the stomach may rise upto 11, which affect pepsin production severely. Maltase, Lactase, Lipase and Sucrase are produced in small intestine and they are active in pH range from 2 to 6.

1. Amylase is an enzyme that catalyses the hydrolysis of starch into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion. 
2. The pancreas and salivary gland make amylase to hydrolyse dietary starch into disaccharides and trisaccharides which are converted by other enzymes to glucose to supply the body with energy. 
3. Foods that contain large amounts of starch but little sugar, such as rice and potatoes, may acquire a slightly sweet taste as they are chewed because amylase degrades some of their starch into sugar. Hence, the enzyme that converts starch to disaccharide is known as amylase.
   

Digestive enzymes are the enzymes that involve in the digestion process which secretes through glands like salivary glands, pancreas, stomach and small intestine but liver does not produce any enzyme. It produces bile juice which provides alkaline condition for enzymatic reaction in small intestine.

The digestive system includes alimentary canal and associated glands to carry out the digestion of food and release the energy stored in these food substances. The nutrients from digested food are then absorbed in the small intestine of the alimentary canal and carried to different organs via the circulatory system. The primary function of the respiratory system is to allow atmospheric oxygen from the air to enter the blood and carbon dioxide from the blood to exit into the air. The endocrine system includes endocrine glands and maintains the homeostasis of the body through hormonal actions. Nervous system serves in the reception of sensory input followed by their integration in the brain and spinal cord and generation of motor output to produce the response. Thus, the correct answer is A.

During the process of respiration organisms breakdown (burn) assimilated food to release energy in the form of ATP which is utilized for performing various activities and CO$ _2$ and water vapour are released as byproducts.

The digestive system plays an important role in the absorption of nutrients into the body. It takes the food we ingest, breaks it down mechanically and chemically in the mouth and stomach. It then absorbs nutrients, fats, proteins, and water in the intestines before eliminating the waste through the rectum. The movement of food in the alimentary canal occurs through peristalsis.

No significant digestive activity occurs in the large intestine. The functions of large intestine are :

After intravenous injection of substance D, it is seen that there is no change in the baseline values of calcium, sodium and glucose level. When the blood pressure is low it will be released, so that the blood pressure is maintained by regulating sodium, calcium and glucose level.