Unlike cnidarians and platyhelminths, round worms have an one-way digestive tract.
Scientists believe the first life form to appear on planet Earth were similar to Monkey's.
I think the correct answer from the choices listed above is option C. The molecule that is called as "the molecule of heredity" is the DNA. It is a molecule that carries the genetic instructions used in growth, development, functioning and reproduction of all living things. Hope this answers the question.
Involuntary Muscles are the muscles that contract and relax automatically, without conscious control by the organism. They are<span> found in the walls of internal organs such as stomach and intestine and bladder and blood vessels. </span><span>One important </span>involuntary muscle<span> is the heart, which keeps beating all day and night. </span>