(a) X = Primary oocytes
(b) Y = Fimbriae, collection of ovum
(c) Z = ampullary - isthmic junction/fallopian tube, the ovum encounters the sperms/fertilization takes place

(a) X- Testicular lobules, location: Testis, outside the abdominal cavity scrotum.
(b) Y - Seminal vesicle, seminal plasma.
(c) Z - Epididymis, function: Storage of sperms.

Yes, if a pregnant woman has high blood pressure, the woman develops preeclampsia, which can threaten the lives of both the mother and the foetus.It can cause low birth weight and early delivery of  foetus,sometimes the child,born very early also may die.
High blood pressure can harm the mother's kidneys and other organs and also lower the number of platelets.

(i)The part labelled A is a vein and B is an artery, as media of artery is thicker than that of a vein and the elastic components of vein is small when compared to that of an attery
(ii)The umbilical artery contains higher amount of urea.The veins carry oxygenated, nutrient rich blood to foetus and arteries carry deoxygenated, nutrient depleted blood away from the foetus.

(i)The mitochondrion present in a cell are collectively referred to as chondriosome
(ii)Mitochondria are associated with cellular respiration (ie.oxidation of cellular nutrients) and energey generation of cell.Thus,it is also referred to as power house the cell.
(iii)Out of the total enzyme present in a cell,mitochondria alone contribute to 70%.The enzymes of Krebs, cycle are present in matrix of mitochondrial membrance) while that of Electron Transport System(ETS) and oxidative phosphorylation are situate in cristae

A diagrammatic representation of meiosis-I and meiosis-II (stage(a-e) represent prophase-I)is given below

(c): Placenta may be defined as the connection between the fetal membranes (amnion and chorion) and the uterine wall (decidua basalis, the portion of the decidua which is directly adjacent to conceptus at the implantation site) for physiological exchange between the fetus and the mother's blood. In mammals, the fetal components of the placenta derive initially from trophoblast, connected with embryonic blood stream, through its contact with yolk sac. Placenta also acts as a major endocrine organs as it secretes hormones such as estrogen, progesterone and hCG that are essential for maintaining a maternal physiological condition appropriate for continued development of the conceptus.

(c): Corpus luteum is formed after the release of secondary oocyte from the Graafian follicle

(d) : If several spermatozoa hit the egg at the same time, even then only one can get entry into the egg because after the entry of one sperm cell, the egg cell becomes impervious (not able to be penetrated) to other sperm cells. This can be done by fertilizinantifertilizin compatibility reaction. Fertilizin of egg interacts with antifertilizin of a sperm of the same species. This interaction makes the sperms stick to the egg surface. The process of penetrating the ovum by many sperms is called polyspermy. Once the sperm cell has penetrated the corona radiata and zona pellucida, its unit membrane fuses with the unit membrane surrounding the egg cytoplasm. Just after the entry of sperm in the egg, a fertilisation membrane is formed (by zona pellucida) in the egg. This membrane prevents polyspermic fertilisation. Amphimixis is the mixing up the chromosomes of a sperm and an ovum.

(d): Implantation is the attachment of the early embryo called blastocyst, to the lining of womb. It begins between the fifth and seventh day after the ovulation and is enabled by the secretion of enzymes. that digest a portion of the endometrium. A blastocyst is composed of a hollow sphere of trophoblast cells, inside of which is a small cluster of cells called the inner cell mass. Trophoblast goes on to contribute to fetal membrane systems. While the inner cell mass is destined largely to become the embryo and fetus

(b) Both assertion and reason are true but reason is not the correct explanation of assertion.

(b) : Epididymis lies along the top and side of testes and is divided into 3 parts - anterior caput epididymis: middle corpus epididymis and posterior cauda epididymis.
The epididymis, besides forming a part of tubular conducting system for sperm transport, in it serves as a storage reservoir for sperms

(c): At about the 14 day of the menstrual cycle, the distended mature graafian follicle ruptures and the ovum or secondary oocyte is extruded into the abdominal cavity. This is, the process of ovulation which is triggered by a surge in LH secretion. The follicle that ruptures at the time of ovulation promptly fills with blood forming a corpus haemorrhagicium. The granulosa cell and theca cells of the follicle lining promptly begins to proliferate and the clotted blood is rapidly replaced with yellowish, lipid rich in luteal cells forming the corpus luteum. This initiates the luteal phase of the menstrual cycle, during which the luteal cells secretes estrogen and progesterone. Progesterone is a steroid hormone that has functions in preparing the uterus for pregnancy. If pregnancy occurs, the corpus luteum persists and if there is no pregnancy the corpus luteum begins to degenerate about 4 days before the next menses (24th day of the cycle) and is eventually replaced by scar tissue, forming a corpus albicans.

(a) : Clitoris of female is the small, spongy and erectile structure which hangs freely from the front end of vulva. It represents the underdeveloped penis. Whereas penis is a finger-like cylindrical outgrowth of abdomen projecting in between the scrotal sacs. Clitoris and penis both originate from the same origin, therefore are homologous.
Homologous organs are those organs which have the same origin and mayor may not have the same function. Clitoris and penis both are the reproductive organs present in female and male respectively. They are originated from the mesoderm layer and both are supplied with the nerves and blood vessels.

(a) Both assertion and reason are true and reason is the correct explanation of assertion.

(c) : Puberty is the period of life at which the ability to reproduce begins and reproductive organs become functional. In male, the puberty is the period between 13-16 years. Puberty in male is controlled by male sex hormone called testosterone, which is secreted by interstitial or Leydig's cells of the testes under the stimulation of interstitial cells stimulating hormone (ICSH) secreted by anterior pituitary. After puberty the seminiferous tubules start producing sperms. The development of secondary sex organs like prostate, scrotum, penis, etc., starts and secondary sexual characters like growth of hair on face, chest, pubis and axillae, broadening of shoulders, deepening of voice due to enlargement of voice box occurs. In puberty (male), height increases due to rapid growth of muscles and bones.

(a) : Scrotum is a place where testes begins to descend during the third month with a concomitant shortening of gubernaculum. Proper descend of testes is essential for complete fertility because sperms needs low temperature by about 2°C from normal body temperature (37°C) to mature. The scrotal sacs has dartos muscles which constantly contracts and relaxes the loose scrotal skin. The loose scrotal skin helps to keep the testicular temperature at 35°C. If the testes do not descend from the abdominal cavity to the scrotum, the high temperature will destroy the sperm producing seminiferous tubules which results in sterility. So, scrotum acts as a thermoregulator and helps in spermatogenesis.