In snails, the hard calcareous shells are secreted by the

Toes of the feet ending in sharp, curved hook suitable for holding and tearing are most likely to belong to the bird with the bill in

The bird's bill adapted for fishing is labelled

The best explanation for the theories of natural selection is that

In the honey bee colony, the drones are

After one week of life, the weight of five chicks of the same sex hatched simultaneously from the eggs of the same hen and fed on the same diet were 45g, 40g...

The basic point of impact by changes which produce mutation is the

In the whistling pine, leaves are reduced to brown scales and young stems are green. This is an adaptation for

The group of insects that have mouth parts adapted for both piercing and sucking is