Question: 94: XO type of sex determination can be found in :
(1) Grasshoppers
(2) Monkeys
(3) Drosophila
(4) Birds
Answer: Option (1)
Explanation:
In the XO type of sex determination, females have two X chromosomes while males have only one X chromosome and no Y chromosome.
Thus, females are represented as \mathrm{XX} and males as \mathrm{XO}.
This type of sex determination is commonly found in insects such as grasshoppers.
Monkeys and Drosophila show the XY type of sex determination,
where males are \mathrm{XY} and females are \mathrm{XX}.
Birds exhibit the ZW type of sex determination, where females are heterogametic
\mathrm{ZW} and males are homogametic \mathrm{ZZ}.
Therefore, XO type of sex determination is found in grasshoppers,
making option (1) correct.