Many kinds of prokaryotes and eukaryotes contain a structure outside the cell membrane called the cell wall. With only a few exceptions, all prokaryotes have thick, rigid cell walls that give them their shape. Among the eukaryotes, some protists, and all fungi and plants, have cell walls.
B . , because I remember this
Answer:
Frequency of recessive allele 
Explanation:
Given -
Total Population size = 919
Number of individual with recessive genotype = 341
Frequency of recessive genotype
Frequency of recessive allele 
Hence, option C is correct
<span>The environmental problem affecting Tuvalu is (B) Climate Change. Its effects can be seen on the change of sea level. Sea level rise, is one of the consequences that made a major threat for Tuvalu. This consequence brought by climate change has a big impact on the islands.</span>
Natural selection is a process by which organisms that are better adapted to their environment tend to D-survive.
Rationale behind not choosing other options:
A. Better adaptation to an environment doesn't lead to an increase in the size of the organisms. The organisms rather become sturdy and efficient at perform optimally as per the requirement in the environment for their survival.
B. Migration takes place to minimize competition for food, shelter, and space in an environment or a habitat.
C. Organisms that evolve new traits tend to better survive in an environment and natural selection favors such organisms over the inefficient ones.
