The trichomes of Utrica cover the leaf and the stem surfaces, each trichome has a base attached to the epithelial layer, and a cell filled with irritant/allergent at the tip, that breaks on mechanical damage, touch, or when attempted to be eaten by herbivores. On breaking the chemical substances are injected into the predator causing unbearable irritation.

Mast cells are the type of white blood cells. They play important role in allergy and inflammatory reactions. They release chemicals like histamine upon exposure to the allergic component.

Allergies, also known as allergic diseases are a number of conditions caused by hypersensitivity of the immune system to typically harmless substances (non-infectious) in the environment.  Symptoms may include red eyes, an itchy rash, sneezing, a runny nose, shortness of breath, or swelling. Hence, Allergy is a noninfectious, unnatural and unusual reaction to a substance or condition.

Allergies, also known as allergic diseases are a number of conditions caused by hypersensitivity (excessive) of the immune system to typically harmless substances in the environment. Symptoms may include red eyes, an itchy rash, sneezing, a runny nose, shortness of breath. Food, insect stings, and medications are common causes of severe reactions.

Antihistamines are drugs that inhibit the action of histamine in the body by blocking the receptors of histamine. When the histamine recepotrs are stimulated by histamine, it may produce allergic reactions, such as itching, hay fever and rash or hives. Antihistamines treat the symptoms of such allergic reactions.
Thus, the correct answer is option (D), 'Allergy'.

Allergies are the reactions or the response given to the antigens which are in the form of particles. Allergy is also termed as hypersensitivity. The cells release IgE antibodies, histamines and other cytokines which manifest the symptoms of the reaction. When the allergen is encountered, the mast cells and basophils undergo degranulation which releases histamine. Histamine is the inflammatory agent. 

Allergies are the reactions or the response given to the antigens which are in the form of particles. Allergy is also termed as hypersensitivity. The cells release IgE antibodies, histamines and other cytokines which manifest the symptoms of the reaction. Allergy may result in urticaria which is the development of skin rash with reddening and swelling of the regions. The allergen results in stimulation of mucus secretion and sneezing which causes rhinitis. The common example of allergy is asthma which results in the constriction of the bronchi and shortness of breath due to the blocking of the airway.  

Autoimmunity is the system of immune responses of an organism against its own cells and tissues. It is the abnormal immune response in which immune system attacks healthy cells.
Thus, the correct answer is option B.

Autoimmune disease is a condition in which our own immune system attacks our own tissues. Rheumatoid arthritis is an autoimmune disease that causes chronic inflammation of the joints.
Grave's disease is an autoimmune disease in which the patient;s own immune system attacks the thyroid gland causing it to produce too much of thyroid hormone.
Hashimoto's disease is an autoimmune condition caused by inflammation of the thyroid gland.
Thus, the correct answer is option D.

An allergy is a hypersensitivity disorder of the immune system. Symptoms include red eyes, itchiness, and runny nose, eczema, hives, or an asthma attack. Out of the given options, only asthma is an allergy. Asthma and allergies often go hand-in-hand. Asthma is a disease of the branches of the windpipe (bronchial tubes), which carry air in and out of the lungs. There are several different types of asthma. Allergic asthma is a type of asthma that is triggered by an allergy (for example, pollen or mold spores).

• Antihistamines are drugs which are used to treat allergic rhinitis and other allergies. Antihistamines can give relief when a person has nasal congestion, sneezing, or hives because of pollen, dust mites, or animal allergy. Histamine is mostly responsible for allergic reactions. Antihistamines block the action of histamines.
  
• A steroid is a biologically active organic compound. Steroids such as corticosteroids are used in the treatment of allergic reactions by reducing inflammation associated with allergies. They prevent and treat nasal stuffiness, sneezing, and itchy, runny nose due to seasonal or year-round allergies. They can also decrease inflammation and swelling from other types of allergic reactions
  
• So, the correct answer is 'Allergy'.

An autoimmune disease is a condition arising from an abnormal immune response to normal body tissue. In an autoimmune disease, the immune system fails to recognize self-cells and produces antibodies against self-cells. Common symptoms include low-grade fever and feeling tired. Autoimmune disease is due to genetic abnormality or other environmental factors. 

The undesirable responses or reaction to any foreign particles produced by the immune system is known as hypersensitivity. These reactions will result into allergic reaction and auto immunity.

Innate immunity works without concern about how much damage happened but to protect the body and the body exposed to an antigen in an environment develops natural innate immunity.

Autoimmune diseases are disorders in which the bodys immune system attacks the body's own cells and organs with proteins called autoantibodies; this process is called autoimmunity. The bodys immune system normally makes large numbers of proteins called antibodies to help the body fight off infections. In some cases, however, the body makes autoantibodies. Examples include systemic lupus erythematosus (SLE), Sjgren's syndrome, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's Disease, rheumatoid arthritis (RA), polymyositis (PM).

Atopy is the condition which has been developed due to exposure to allergens in which the person is susceptible to allergic reactions. This is an inherited syndrome. The person is more likely to develop the allergic reactions like rash, rhinitis, asthma, etc when encountered with the allergen.