Answer: Option A. -> Tunica albuginea
:
A
The testes (testicles) are the male gonads, that is they are the primary male reproductive organs. The multilayered tunica covers the testes. It facilitates blood supply to the testes and creates a partition between sperm-producing regions of the testes. The tunica albuginea is the fibrous covering of the testes. It is a dense blue-grey membrane, composed of bundles of white fibrous connective tissue.

Answer: Option C. -> Ciliated epithelium in the fallopian tube
:
C
Simple cuboidal epithelial tissue consists of a single layer of cuboidal cells on the basement membrane. At some places the cuboidal epithelium is ciliated, like in the fallopian tubes. The beating movement of the cila helps in moving the ovum from the fallopian tube down the reproductive tract.

Answer: Option C. -> Progesterone
:
C
The major events in menstrual cycle include menstruation, the follicular phase and the luteal phase, after which the next cycle begins. Both LH and FSH attain a peak level in the middle of the cycle (about the 14th day). Rapid secretion of LH leading to its maximum level during the mid-cycle, called LH surge, induces rupture of Graafian follicle and thereby the release of ovum (ovulation). The ovulation (ovulatory phase) is followed by the luteal phase during which the remaining parts of the Graafian follicle transform as the corpus luteum. The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium. Such an endometrium is necessary for implantation of the fertilised ovum and other events of pregnancy.

Answer: Option A. -> Cervix        
:
A

The uterus is also called the womb. The cervix is the lower part of the uterus that connects the uterus to the vagina. The function of the cervix is to allow the flow of menstrual blood from the uterus into the vagina. It also aids in carrying sperm from the vagina to the uterus. It also widens during childbirth to allow the passage of the baby.   

Answer: Option D. -> Secondary sexual characteristics include the ovary and penis
:
D

Primary sexual characteristics are present from birth and are directly concerned with reproduction and allow the differentiation of males and females. The ovary in females and penis in males are primary sexual characters. Secondary sexual characters appear during puberty due to the hormones released during this time. Primary and secondary sexual characteristics differentiate males and females in a sexually dimorphic species. Secondary sexual characteristics are not concerned with reproduction or production of gametes.

Answer: Option D. -> All of the above.
:
D
Endometriosis is a disease in which tissue that normally grows inside the uterus (endometrium) grows outside it. Most often this is on the ovaries, fallopian tubes, and tissue around the uterus and ovaries; however, in rare cases, it may also occur in other parts of the body.

Answer: Option A. -> It has almost equal quantity of cytoplasm as an uncleaved zygote but much more DNA
:
A
A morula is an embryo at an early stage of embryonic development, consisting of cells (called blastomeres) in a solid ball contained within the zona pellucida. The morula is produced by embryonic cleavage, the rapid division of the zygote. The increase in the number of cells doesn't change the size of the original mass. The divisions are rapid because there is no net growth of the embryo. In the absence of growth, the cell number in the embryo increases while the cell size decreases. Thus, it has an almost equal quantity of cytoplasm as an uncleaved zygote but much more DNA.

Answer: Option B. -> After the ovum has been penetrated by a sperm
:
B

In mammalian ovum, during maturation phase, meiosis occurs. Nucleus shifts towards animal pole and undergoes meiosis-I. After fertilization the second meiotic division is completed with unequal cytoplasmic cleavage. This forms a large cell called the ootid, with essentially whole of the cytoplasm and a very small cell, the second polar body.

Answer: Option C. -> P - iv                   Q - iii                  R - ii                 S - i
:
C

The sperm is divisible into 3 parts - the head, midpiece and tail. The head consists of acrosome which contains hyaluronidase and proteolytic enzymes, which help in penetrating the ovum during fertilisation. Along with the acrosome the head of the sperm also consists of a haploid nucleus and centrioles. The midpiece of the sperm has mitochondria which produce the energy necessary for sperm motility. The tail is mainly involved in providing motility to the spermatozoon, and propels it forward.

Answer: Option C. -> mitochondria and 9 + 2 arrangement of microtubules
:
C

A sperm is a microscopic structure composed of a head, neck, a middle piece and a tail. A cross section at the midpoint of the middle piece of a sperm will show mitochondria and 9 + 2 arrangement of microtubules. The middle piece possesses numerous mitochondria, which produce energy for the movement of the tail that facilitates sperm motility essential for fertilisation.