B.

Sympathetic and parasympathetic nervous system are the parts of autonomic nervous system. Autonomic nervous system is a part of peripheral  nervous system that supplies stimulation via motor nerves to the smooth and to cardiac muscles (the involuntary muscles) and to the glands of the body. The activity of the ANS is controlled principally by the medulla oblongata and hypothalamus of brain. Sympathetic and parasympathetic nervous system tend to work antagonistically on the same organ.

B.

Millipede: Millipedes belongs to Phylum Arthropoda. Millipedes arc called thousand leggers because of possession of numerous legs. Inspite of this they move very slowly.

Duckbill platypus: It is an egg laying mammal of Phylum Chordata and Class Mammalia. 

Silverfish : Lepisma saccharina is commonly known as silver fish because of its glistening silvery white fish like body. It belongs to the insect Order Thysanura.

Sea anemone : Sea anemone (Admasia), belongs to Phylum Cnidaria shows commensalism. It is found attached to the empty shell of gastropods occupied by hermit crab. Its body wall is two layered i.e.. outer epidermis and inner gastrodermis. In between these two layers is present mesogloea.

D.

a muscular diaphragm and milk producing glands.

All mammals without any exception are characterized by a muscular diaphragm and milk producing glands.

D.

Oxyntic (or parietal) cell is present in the wall of the stomach that produce HCI which forms the part of gastric juice. Oxyntic cell also produce intrinsic factor which is involved in the absorption of vitamin B₁₂ in the small intestine. The pH of gastric acid is 2-3 in the stomach of the lumen. The acidity being maintained by the proton pump, a H⁺/ K⁺ ATPase.

Alpha cell ofislets of langerhans secrete glucagon hormone which raises blood glucose level by stimulating liver to convert glycogen to glucose and by stimulating the conservation of fatty acids and amino acids to glucose.

Kupffer cells arc specialized macrophages that disposes of old blood cells and particulate matter. Kupffer cells, named after Karl Wilhem Von Kupffer, are found in the bloodstreams and in the liver, attached to the walls of the sinusoids.

Sebaceous gland is a simple or branched glands in the skin that secrete an oily substance, sebum which is fatty mildly antiseptic material that protects, lubricates, and waterproofs the skin and hair and help prevent dessication.

A.

Cell A is the rod cell found evenly all over retina

The retina contains two types of photoreceptors, rods and cones. The rods are more numerous, some 120 million, and are more sensitive than the cones. However, they are not sensitive to color. The 6 to 7 million cones provide the eye's color sensitivity and they are much more concentrated in the central yellow spot known as the macula. In the center of that region is the " fovea centralis", a 0.3 mm diameter rod-free area with very thin, densely packed cones.