Answer:
cell > tissue> organ> system
Explanation:
The answer is Vas deferens
Answer:
voluntary, you did it by will
Explanation:
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.