Question

which of the following determines biological sex in humans?
a the number of autosomes
b presence of an x and a y chromosome
c the zygotes mitochondria
d whether fertilization occurs internally or externally

Explanation:

• Autosomes (Option A) are non - sex chromosomes and do not determine biological sex.
• Mitochondria (Option C) are involved in energy production and not in sex determination.
• Fertilization mode (Option D) is about how fertilization happens and has no relation to sex determination.
• In humans, biological sex is determined by the presence of sex chromosomes. Females have \(XX\) (two \(X\) chromosomes) and males have \(XY\) (one \(X\) and one \(Y\) chromosome). So the presence of \(X\) and \(Y\) chromosomes (Option B) determines biological sex.

Answer:

B. Presence of an X and a Y chromosome