Identify the type of sex determination method in grasshopper.

The correct answer is Option (2) → XX-XO type

In the XO type of sex determination, the female has two X chromosomes (XX) and the male has only one (XO), with no Y chromosome. The female makes one kind of egg, each with an X. The male makes two kinds of sperm, some with an X and some without. An egg fertilised by an X sperm becomes a female, and an egg fertilised by a sperm without X becomes a male. Grasshopper is an example.

(1) XX-XY type — Incorrect. Here the male has one X and one Y chromosome. This is the type in humans and Drosophila.

(2) XX-XO type — Correct. The male has one X chromosome only.

(3) ZZ-ZW type — Incorrect. Here the female has two different chromosomes (ZW) and the male has two alike (ZZ). This is the type in birds.

(4) ZO-ZW type — Incorrect. There is no such type. The bird type is ZZ-ZW.

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NCERT Extract:
Sex Determination – …