Give an example of something that heat energy can pass through easily and an example of something that it cannot easily pass through.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Asmall number of finches are removed randomly from the wild and placed in a protected bird area. they are given as much food as they need and have plenty of space. why would natural selection not occur in this population? a. there is no reason for genetic mutation to occur. b. the birds compete for limited resources, c. the population has not reached carrying capacity. d. there is no genetic variation in the finches.

In natural selection, what is actually “selected? ” a) alleles are directly selected b) genotypes are directly selected c) phenotypes are directly selected d) entire populations are directly selected