Biology

Light

Temperature

Oxygen

water

Carbondioxide

scales in fishes

scales on leaves

thick leaves

spine in plants

succulent stem

Claws

Gular fold

Scaly skin

Nuchal crest

tail

a device for survival during a period of extreme food and water shortage

A method of survival adopted by plants during dry season

Movement of animals over long distance

A method of survival adopted by animals under favourable condition

A device for rapid multiplication during abundance of food

partial selection

artificial selection

natural selection

mutation

colonization