Why is apple called a false fruit? Which part(s) of the flower forms the fruit?
Apple is called a false fruit because in apple, the thalamus also contributes to fruit formation along with the ovary. In most plants, by the time fruit develops from the ovary, other floral parts degenerate and fall off. However, in species like apple, strawberry, and cashew, the thalamus contributes to the fruit.
In most plants, the ovary develops into the fruit. The wall of the ovary develops into the wall of the fruit called pericarp. The transformation of ovules into seeds and ovary into fruit proceeds simultaneously.
Explanation
This question tests the student's understanding of fruit formation in angiosperms. The textbook clearly distinguishes between true fruits (developing only from the ovary) and false fruits (where other floral parts like thalamus contribute). Apple is a classic example of a false fruit mentioned in Chapter 1 (Sexual Reproduction in Flowering Plants) where the thalamus contributes significantly to fruit formation.