He used a simple microscope
Answer:
The correct answer is None of these choices are correct.
Explanation:
Crossing over doesn't occur only between heterozygous genes, it also doesn't happen only in some chromosomes and it never reduces de variation, otherwise, the crossing over is one of the main causes of variation among species.
Just like in humans, radioactive material can damage plant tissues as well as inhibit growth. mutations are possible due to damage caused to the DNA. radioactive material in soil can prevent nutrient from being taken in by plants, causing it to be infertile.
I believe your answer would be:
A. Fossils.
Explanation:
Because they are the preserved remains or traces of animals, plants, and other organisms from the past. They're also important evidence for evolution because they show that life on earth was once different from life found on earth today.
Hope I helped, good luck! =)
When you take blood pressure, it is expressed in a fraction. The top number of that fraction is systolic pressure- the amount of pressure in your arteries during contraction of your heart muscle... I hope this helped! :)