Answer: D - Mutations occur randomly through changes in DNA.
Explanation:
Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses. Germ line mutations occur in the eggs and sperm and can be passed on to offspring, while somatic mutations occur in body cells and are not passed on.
Evolution caused different anatomy..
the brain is differently wired in men and womens
Humans have inadvertently promoted the evolution of insects that are resistant to insecticides by trying to control pest with chemicals. The evolution of insecticide resistance is becoming a serious problem through out the world. It is important to identify patterns of insecticide use whereby insecticides can be used in integrated pest management programmes to help control insect numbers, however in a manner that will reduce the evolution of resistance species.
Answer:
The skeletal muscle is stimulated by means of action potentials that are caused by the neuromotor plate. These action potentials are one after the other and can become cumulative once the muscle fibers pass the refractory phase of the action potential.
The refractory stage is that stage in which action potentials are not admitted, therefore where the muscle fibers do not accept stimuli to contract.
Once this refractory stage is over, more action potentials can be admitted, which would be summative and the muscle fiber would contract with greater power.
Explanation:
If a muscle is repeatedly stimulated, the contraction will be weaker or the muscle will fatigue more easily, triggering muscle failure.
If the muscle is stimulated with a longer pause between contraction and contraction, the action will be performed with more power.