C.

lipids and proteins

Major constituents of plasma membranes are Protein(60%) and lipids(40%). The percentage of carbohydrates ranges from 1-10 which are in the form of glycoproteins or glycolipids.

Proteins may be extrinsic(peripheral) and intrinsic(integral) while lipids may be phospholipids, sphingolipids, glycolipids and sterols(eg- cholesterol).

C.

Lysosomes

Endoplasmic reticulum, mitochondria and chloroplast are double-membraned cells organelle whereas lysosome is a single membrane cell organelle.

D.

nutrition

Chloragogen cells or yellow cells are present in the region of intestine in Pheretima. The exact function of these cells is not fully known but it is believed that they are concerned with storage of reserve food and also excretory in function. Chloragogen cells are analogous to liver of vertebrates.

D.

FSH and LH

Gonadotropins or gonadotropic hormones are as follows.

(a) Follicle Stimulating Hormone (FSH) : It stimulates growth of ovarian follicles and their secretion of oestrogen in the female and spermatogenesis in the male.

(b) Interstitial Cell Stimulating Hormone (ICSH) : It activates the Leydig's cells of the testis to secrete androgens. In female it stimulates the corpus luteum of the ovary to secrete progesterone. In female ICSH is termed as LH (Luteinizing Hormone).

B.

Urea

Urea is the main nitrogenous excretory product of ureotelic animals. It is produced by liver cells from deaminated excess amino acid via urea cycle or Omithine cycle. Urea is released outside the body in the form of urine through the kidneys.