Alayer of hard, thick dense material that contains minerals

Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated he the same distance, which pair experiences the frayed gravitational attraction?

The distant ancestors of tigers may have had bodies without stripes. use the theory of natural selection to explain how tigers may have evolved to have stripes.

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic