What color is used to represent crust that is 100 million years old? 135 million years old?

Which of the following occurs after a natural or unnatural disturbance in an ecosystem

Creation of an unnaturally uniform sample to represent a diverse populationcan be avoided by: a. including only willing b. asking another scientist for .c. choosing only identical participants. d. selecting individuals at random.

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