Tag: biology

All animals do not contain chromosomes. In some cases, sex is determined by environmental variables (such as temperature) or social variables (e.g. the size of an organism relative to other members of its population). Therefore, (d) is the correct answer.

There is one X chromosome present in a male. Sex pair of chromosome XY represents the male human.

There are two X chromosomes present in a female. Sex pair of chromosome XX represents the female human.

When a sperm containing Y chromosome fertilises an egg with X chromosome, the zygote develops into a male child with XY as the sex chromosome. Because Y chromosome is only found in males.

A zygote is diploid. Hence it will have 44 autosomes. A sperm can have either of the two sex chromosomes X or Y while the egg has only one sex chromosome X. If the sperm containing the X chromosome fuses with the egg, the child born will be a female. If the sperm containing the Y chromosome fuses with the egg the child born will be a male. Thus the correct answer is option A.

XX chromosomal pair determines that a child is a female. XY combination determines that the child is a male. Thus, an egg of a female will always contain and X chromosome. 50% of the sperms contain X chromosome and 50% of sperms contain Y chromosome. Thus when an egg is fertilized by a sperm containing X chromosome, the combination of XX is paired thus giving birth to a girl child.

In humans, males and females have differences in sex chromosomes. Human cells are having two types of chromosomes: autosomes and allosomes. Allosomes present in a male is XY and those present in a female are XX. There are no differences in the cytoplasm or membrane. The chromosome is present inside a nucleus, so you can think of the nucleus also as the correct answer but when a chromosome is given as an option, it is a better choice.

A human female produces only one type of ovum having half the number of autosomes and one X chromosome. However, a male produces two types of sperms having half the number of autosomes and either an X or a Y chromosome. In case, the sperm with X type of chromosome fertilizes ovum then a female child is produced and if the sperm with a Y chromosome fertilizes the ovum a male child is produced. Hence, the type of sperm that actually fertilizes the ovum determines the sex of the baby.

• Father determines the sex of the child as there are two types of sperms ( 23+XX and 23+XY) while all eggs are same (23+XX).
• Father inherits the character to both son and daughter as each offspring whether boy or girl receives half of their genome from mother and another half from father.
• So, the correct option is 'None of the above'.