Question

Sex Determination in Human -

• A. XY
• B. XO
• C. ZW
• D. Haplodiploid

Hint:

Humans: Female = XX, Male = XY. The father determines the sex of the offspring because sperms carry either X or Y chromosome.

Answer 1

The Correct Option is A

Concept: Sex determination is the mechanism through which the sex of an individual is established. Different organisms exhibit different systems of sex determination. Humans possess an XX-XY type mechanism of sex determination.

Step 1: Understand the chromosomal constitution. In humans: \[ \text{Female} = XX \] \[ \text{Male} = XY \] The female produces only X-bearing ova. The male produces two kinds of sperms: \[ X \text{-bearing sperm} \] and \[ Y \text{-bearing sperm} \]

Step 2: Determine how sex is decided. If an X-bearing sperm fertilizes the ovum: \[ XX \] a female child is produced. If a Y-bearing sperm fertilizes the ovum: \[ XY \] a male child is produced. Thus, sex determination in humans follows the XY mechanism.

Step 3: Examine other options. XO occurs in certain insects. ZW occurs in birds. Haplodiploidy occurs in honey bees and some other insects.

Step 4: Conclude. Humans exhibit XY type sex determination. \[ \boxed{\text{XY}} \] Hence, the correct answer is \[ \boxed{(A)\ \text{XY}} \]