The answer is D. During sexual reproduction, crossing-over occurs where chromosomes exchange genes to make the gene pool bigger and have more variety.
Answer:
physical change alert the form of appearance of the matter but does not turn any substance in the matter into a different substance.
They are not made up of living cells.
viruses can’t reproduce or replicate themselves on their own and need a host cell. They don’t grow and can’t make their own energy....
Answer:
Evolution of cyanobacteria
Explanation:
Early earth was reducing therefore there was no oxygen on early earth. Oxygen first came on the earth due to the evolution of cyanobacteria on earth. Cyanobacteria were the first aerobic bacteria on earth.
This bacteria was able to conduct photosynthesis and split water into Hydrogen and oxygen. This oxygen is released in the atmosphere and created the aerobic environment on the earth.
Cyanobacteria used sunlight energy to split water and by this, they are able to make their own food in the form of carbohydrates. Therefore the correct answer is cyanobacteria.