Answer:
Arthropods have a tough, non-living outer shell called exoskeleton, which protect their soft bodies while echinoderms have living endoskeletons, which develops within the deeper skin or body tissues and act as their protective covering.Explanation:
Answer:
Antibiotics have helped in a speedy recovery for human illnesses over the past century.
Explanation:
Because anti biotics were not present centuries ago, many would get sick and even die. However, antibiotics work by affecting things that bacterial cells have but human cells don't. This helps to fight off the bacterial cells and fight infections and viruses, leading to a speedy recovery.
Answer:
I, II, III
Explanation:
A threshold stimulus is a stimulus that is capable to produce a response in excitable tissues such as neurons and muscle fibers. At threshold potential, the outward movement of K+ and inward movement of Na+ become equal to each other. When the potential exceeds the threshold potential, more and more Na+ enter the cell to depolarize it and to allow the opening of Na+ channels. Therefore, to fire an action potential, the threshold must be exceeded.
Conduction of action potential is all or none phenomenon which means that either it occurs or it does not occur. As an impulse is passed by each successive part of an exon, it enters the refractory period during which there is no conduction of nerve impulse. It ensures the one-way conduction of impulse from the cell body to the axon terminal only.
The number of consumers increases
A) be unable to maintain homeostasis
