Which statements about carbon-14 dating are true?

Which of the following examples can cause gene flow between populations? a. an increase in predators to a population of zebra b. a volcanic eruption that kills half of a population of mice c. bird droppings that contain seeds from a different location d. a person that sprays a toxin on a group of mosquitoes

What links the two strands in a dna helix together in the middle? a. phosphate groups b. sugar rings bonded together c. proteins d. bases with hydrogen bonds

Why is it important to reduce the number of chromosomes in half when forming gametes for sexual reproduction?