Given below are two statements:

Statement I: Vas deferens receives a duct from seminal vesicle and opens into urethra as the ejaculatory duct.

Statement Il: The cavity of the cervix is called cervical canal which along with vagina forms birth canal.

In the light of the above statements, choose the correct answer from the options given below:

How many secondary spermatocytes are required to form 400 million spermatozoa?

Arrange the components of mammary gland. (from proximal to distal).

(a) Mammary duct

(b) Lactiferous duct

(c) Alveoli

(d) Mammary ampulla

(e) Mammary tubules

Choose the most appropriate answer from the options given below :

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): During pregnancy the level of thyroxine is increased in the maternal blood.

Reason (R): Pregnancy is characterised by metabolic changes in the mother.

In the light of the above statements, choose the most appropriate answer from the options given below: