Answer:
Fenestrated capillaries
Explanation:
Fenestrated capillaries are found in some tissues where there is extensive molecular exchange with the blood such as the small intestine, endocrine glands and the kidney.
Answer: Natural selection is selection due to environmental conditions from random genetic mutations in a population. Among the variants in a population, some will be slightly better adapted to conditions and will eventually out-compete the rest of the population. Survival of the fittest actually means survival of the best adapted, or fittest for purpose, i.e. to survive and thrive.
Explanation: This phrase has caused much miunderstanding of the evolutionary process. ‘Fittest’ has been equated with biggest, or strongest or fastest, but this was a description originating in the nineteenth century, when it was understood quite differently.
Natural selection arises from genetic variation in a population. Jaques Monod, an esteemed scientist, described evolution as where chance and opportunity meet. Chance lies in the genome of a species, random mutations, and the resulting genetic variation in the population.
Opportunity lies in the environment. Environmental change creates opportunities for some, extinction for others. Opportunities can also be from exploiting new environmental niches.
Natural selection is the process by which some random genetic variation gives some of a population a competitive advantage. competition eventually results in one population out-competing all others in its niche. The end-result of competition in nature is monopoly.
But this process continues and further random mutations can result in another population becoming better adapted. That is the actual meaning of survival of the fittest: in modern terms we might say ‘fittest for purpose’, that is, the species orvpopulation best adapted to survive and thrive in that environment.
