Traits can also be
, which means they can be masked

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.

Which of the following are the ingredients that go into the plant and are needed for photosynthesis? select all that apply. 1.) soil 2.) seeds 3.) carbon dioxide 4.) minerals 5.) glucose (sugar) 6.) water 7.) light energy (sunlight) 8.) oxygen 9.) air

List five ways we are indebted to phytoplankton