Answer:
Explanation:
The central nervous system (CNS) does not have capacity to repair itself but, the PNS or the peripheral nervous system can repair and regenerate itself. The PNS can regenerate its damaged axon only when its cell body or cyton and its neurilemma are intact. The proximal end of the cyton has growth cones. The axon grows from the cones.
Answer:
To make sure that the experiment is accurate, the scientist must make carry out an appropriate observation, which would lead to the formation of good hypothesis. Good experimental method is an other criteria to look forward for the accurate experimental results. Methods are applied in collection of data and other things and in compiling results using statistical methods to carry out an accurate experiment.
Answer:
C. disruptive natural selection
Explanation:
Disruptive selection is a type of natural selection in which extreme phenotypes are favored over intermediate phenotypes in a population. Environmental change is a major factor that can bring about disruptive selection. The individuals with the extreme phenotypes adapt well and are able to survive in the particular environment, while those individuals with intermediate phenotypes would hardly survive or be greatly reduced in number.
The gray rock outcrops and the brown soils of the Island favors the survival of mice with brown and gray fur color respectively. The fur colors of these two extreme phenotypes in the population of mice, have helped both varieties against Hawks as their main predators, hence establishing their existence on the Island.
Answer:
Although elephants and hyraxes at first don't seem to have many similarities, a closer look has led many scientists to believe that these animals are evolutionarily closely related.
Elephants and Hyraxes share many reproductive characteristics that indicate a common ancestor: The location of the testicules in these animals diverges from most mammalian species, remaining inside the retroperitoneal abdomen. Females have similar placental origins and long gestation periods and the location of the mammary glands in both orders (above the front legs) is a unique feature among non-primate mammals. Hyraxes' tusks develop from incisor teeth, similar to elephants, and in both cases nails develop into flattened, hoof-like structures.
Molecular evidence has also been used to confirm the hypothesis of evolutionary relatedness between the two orders, as similarities in some gene sequences in mitochondrial DNA and other molecular components. Both animals have some physiological similarities and cognitive characteristics (such as the presence of a powerful long-term memory) that support the possibility of evolutionary proximity.
The fossil record indicates that in the Eocene period hyraxes were dominant herbivores in Africa, with several species, reaching much larger sizes than today and occupying different ecological niches, indicating that elephants and hyraxes may have been very similar millions of years ago.
