a. | Humans are sexually reproducing and viviparous. |
b. | The ovaries in human females produce only hormones. |
c. | The mammary glands are one of the female secondary sexual characters. |
d. | A normal human sperm is composed of a head, neck, and middle piece only. |
a. | Interstitial spaces of testis contain Leydig cells and other immunologically competent cells. |
b. | Testes are situated inside the abdominal cavity within a pouch called scrotum. |
c. | The scrotum helps in maintaining the low temperature necessary for spermatogenesis. |
d. | Each lobule of testis contains 250 seminiferous tubules in which sperms are produced. |
Column-I | Column-II | ||
a. | Milk | (i) | Spermatids are transformed into spermatozoa |
b. | Primary spermatocyte | (ii) | Stored in the cavity of alveoli |
c. | Spermiogenesis | (iii) | First menstruation begins at puberty |
d. | Menarche | (iv) | Periodically undergo meiosis |
(a) | Spermatogonia produce sperm cells by spermatogenesis that begins at puberty. |
(b) | All spermatogonia periodically undergo meiosis. |
(c) | A primary spermatocyte completes first meiotic division during embryonic development. |
(d) | The secondary spermatocytes have only 23 chromosomes each. |
Assertion (A): | During pregnancy, the level of several hormones like estrogens, progestogens, cortisol, prolactin, thyroxine, etc are increased several folds in the maternal blood. |
Reason (R): | Increased production of these hormones is essential for supporting the foetal growth, metabolic changes in the mother, and maintenance of pregnancy. |
1. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
2. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
(i) | Relaxin is secreted by the ovary in the later phase of pregnancy. |
(ii) | Inner cell mass differentiates into ectoderm and endoderm just before implantation. |
(iii) | Implantation leads to pregnancy. |
(iv) | Embryo with 8 to 16 blastomeres is called morula. |