What is significance of crossing over during meiosis?

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons

The wind speed in the region between cities a and b was probably the greatest at noon on which day?

Name three things that show evidence of evolution. write one sentence for each, explaining why it demonstrates evidence. (9 points)