Sexual Reproduction

The correct answer is option (B): Germ cell → sex chromosome
Human sex is determined using the XY sex-determination mechanism. The formation of the phenotypic distinctions between male and female humans from an undifferentiated zygote is the result of intricate procedures. Chromosomes are found in the nucleus of a cell. In humans, there are typically 23 pairs of chromosomes, 22 of which are autosomes, and the last pair, which defines the individual's sex. Males have pairs of XY chromosomes, whereas females have XX chromosomes. At the moment of fertilisation, an individual's sex is decided when an X or Y chromosome from the sperm cell fuses with the X chromosome in the egg cell. The gender of the baby is decided by which sperm fertilises the egg. The kid will be a female if the egg is fertilised by sperm that has the X chromosome. A male will be born if sperm carrying the Y chromosome fertilises the egg.

The correct answer is option (A): Tapetum
In the anther of flowering plants, there is a unique layer of nutritive cells called the tapetum that lies between the sporogenous tissue and the anther wall. Tapetum serves as a source of pollen coat precursors and is essential for the nourishment and growth of pollen grains. The cells are frequently bigger and have many nuclei. Tapetal cells go through mitosis as sporogenous cells divide their nuclei. Many mature tapetum cells develop multinucleate because this mitosis is frequently abnormal. Polyploidy and polyteny are also sometimes observed. The tapetum helps pollen grains grow by supplying them with nutrients and regulating chemicals thanks to its very vast nuclear composition.