Fibrinogen is a protein. It is involved in coagulation. It is not present in serum.

Sodium ions are present in maximum concentration in blood plasma. The normal concentration range is 135 - 145 mmol/l.

Pulmonary artery carries deoxygenated (impure) blood to the heart.

Systemic aorta collects oxygenated blood from left ventricle and distributes it to the whole body.

During diastole, blood enters the heart from the venous vessel.

Arteries are thicker than veins because they receive blood at very high pressure from the heart and supply it to the whole body.

Bicuspid valve is present between left atrium and left ventricle. It has two flaps. It guards the opening between left atrium and left ventricle.

Lymph nodes function in the destruction of pathogens. Lymphocytes in lymph destroy harmful pathogens and protect the body from various diseases.

The number of chambers in the heart of amphibians, fish, humans and elephants respectively are 3, 2, 4 and 4.

Transpiration increases in high temperature.

Companion cells help the sieve tube cells in the transportation of food. Thus, they assist in translocation of food.

During ventricular contraction, systolic pressure is exerted by blood against the wall of artery.

Root pressure helps in the ascent of sap by pumping sap into xylem in roots.

In amphibians and reptiles, incomplete double circulation is observed. In incomplete double circulation, the blood comes to the heart through two different routes, but goes out through a single route.

Dendritic cells and macrophages are monocytes. Dendritic cells function in processing antigen material and present it on cell surface to T-cells of immune system. Macrophages function in detecting, engulfing and destroying pathogens and apoptotic cells.