Which characteristic is shared by all arthropods?

a jointed legs

b gills

c endoskeleton

d calcified hard shell

Ascientist separates a population of mice into two groups. what would most likely increase the rate of speciation in this population. a. teach the two groups different tricks b. allow the two groups to breed with each other c. put the two groups in different environment d. have the two groups live in identical ecosystems

How many chromosomes does each human cell contain? a. 23 chromosomes b. 26 chromosomes c. 43 chromosomes d. 46 chromosomes

Speed is the ratio of the distance of an object moves to