There are three sources of genetic variation: mutation, gene flow, and sexual reproduction. A mutation is simply a change in the DNA.
Answer:
Yes because we use our brain to write, read, draw, drive a car, or pretty much anything we do. Even sleeping our brain is working. But at a slower pace. The brain never stops working.
Explanation:
Answer: The correct answer is-
A. organs, but no true body cavity.
Based on the presence of body cavity ( also called coelom), multicellular animals can be classified as acoelomates ( no true body cavity), coelomates ( having true body cavity), pseudocoelomates ( false body cavity).
Roundworms are pseudocoelomic. This means that organs are present but the body cavity is not lined by mesodermal epithelium.
Body cavity is present between the external wall of body and the intestine and it baths the different body organs.
Thus, option A) is the right answer.
