He wanted to observe cells in the fish’s eye, but he saw nothing. explain why.

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.

How does photosynthesis show the conservation of mass and energy?

Which statement is not an accurate description of meiosis? a) meiosis produces offspring that are genetically diverse. b) meiosis produces offspring that are identical to the parent. c) in sexual reproduction half of the genetic material comes from the father (sperm) and half of the genetic material comes from the mother (egg). d) meiosis decreases the number of chromosomes by half so that when a sperm fertilizes an egg, the resulting zygote has the correct number of chromosomes.