Answer: b. Muscles
A metazoa is a division of animal kingdom that includes all animals expect protozoa and sponges. Metazoa division includes multicelluar animals, which exhibit highly differentiated cells. They have muscular and nerve system and well coordinated tissues and organs. Locomotion requires a coordination activity of muscular, skeletal and neural system. It is mainly achieved by contraction and relaxation of muscles that occurs due to specialized muscle proteins named as actin and myosin which receives signals from nerves.
Hence, locomotion in metazoa is due to contraction of muscles.
Answer:
Basically, the Atrioventricular valves are Mitral and Tricuspid valves located between the atrium and ventricles. Their main functions is to “prevent the backflow of blood from the ventricles into the atrium during the ventricular contraction (systole).
Explanation:
It isn't necessary to stage a play in one's own imagination for one to be able to read the play properly. For that reason, I would say that the answer is False.
Actors don't necessarily carry out plays in their imagination but rather just act it out, so the answer indeed would be false in this case.