When a thin plant or animal leaves an impression in sediment that becomes sedimentary rock, this is a fossil.

Ashort, vertical, solid, or fleshy stem possessed by gladiolus and which is used in reproduction is termed a

Hurry which of these is true about index fossils? a) are very scarcely found b) used as guides in relative dating c) found in the youngest layer of the rock d) used as reference points in absolute dating

How does natural selection change thephenotypes within a population over time?