In a population of a grasshopper species, the chromosome number of some members is 23 and some other members possess 24 chromosomes. The 23 and 24 chromosome-bearing members in this species are ____ .

Question

Accepted Answer

C. 1. **Recall the sex-determination system in grasshoppers.**
Grasshoppers follow the **XX-XO** type of sex determination, where females carry a pair of X chromosomes and males carry only a single X chromosome with no corresponding partner.

2. **Write the sex chromosome makeup of each sex.**
Given that the autosome number stays the same in both sexes,

$$
	ext{Female} = 	ext{Autosomes} + XX, \qquad 	ext{Male} = 	ext{Autosomes} + X0
$$

3. **Compare total chromosome counts.**
Since the male has **one fewer** chromosome than the female (missing the second X),

$$
	ext{Male total} = 	ext{Female total} - 1
$$

4. **Apply this to the given numbers.**
Therefore, the member with **23 chromosomes** must be the **male**, and the member with **24 chromosomes** must be the **female**.

Hence, the correct answer is **Option C, males and females, respectively**.