Question

1.a Name the male crayfish appendages that are used to inseminate the female.

b. Name the small arthropod found in huge numbers at polar regions.

c. Name the endocrine gland that stimulates immune system cell production.

d. Name the sheet of muscle that inflates a mammalian lung.

e. Name the heart valve that prevents backflow to the left atrium.

f. Name the mammalian tissue that secretes mucous and lines the entire body wall.

g. Name the rat organ that has bacteria to digest cellulose in plant cell

Answer 1

(a) First Swimeret is the appendage in the male crayfish tat is used to inseminate female (is transfer sperm to female ).The swimmerets are present on the ventral side in the abdominal region.

(b) Mites and Springtails are present in huge number in polar areas.

(c) Thymus. It is an endocrine gland present in the mediastinum in the thorax of children.It helps in development of T-cells.By adulthood it involutes and becomes dormant.

(d) Diaphragm. It is a muscle separating thorax and abdomen.During inspiration or inflation of lungs diaphragm contracts and is pushed down to allow lungs to expand.

(e) Mitral valve also know as Bicuspid valve.

(f) Epithelial tissue .

(g) Caecum . It does not have enzymes to digest cellulose but it contains fermenting bacteria.The first pass of food through the digestive tract does not provide good opportunity to digest cellulose but if the rats re- ingest fecal pelleted, the cellulose in it is further broken by the bacteria easily because the food particles are finer when they re-ingest fecal pelletes.