Answer: all cacti in the area.
Explanation:
Population is the total number of organisms of the same specie present in an given area.
Based on the given area (desert), all the cacti, best describes population.
Note that whenever different species (lizards, owl etc) are considered like in options B, C and D, you are referring to a community
Thus, all cacti in the area are considered as population.
Because there is insufficient evidence to support the idea that all chimpanzees use tools. the scientist would need lots of hard evidence supporting this conclusion (lots of chimpanzees using tools)
refers to a single inherited phenotypic trait that is controlled by two or more different genes. ... Each of the genes that contributes to a polygenic trait, has an equal influence and each of the alleles has an additive effect on the phenotype outcome.