Why is the gravitational force between Earth and Venus very close to the gravitational force between Earth and Jupiter?

As a small change in a person's dna can cause a genetic disorder

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 can you tell the difference between rough er from smooth er?