Which statement describes the relationship between plants, animals, and the carbon cycle? Plants use carbon and release oxygen, and animals release carbon and use oxygen.
Animals fix carbon and release oxygen, and plants release carbon and use oxygen.
Animals fix carbon through respiration, and plants fix carbon through photosynthesis.
Plants use carbon when they decompose, and animals release carbon when they decompose.

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.

Question#29: why does the tropical ocean have a greater temperature range than the temperate ocean?

Which of the follow describes a disadvantage secondary sources have compared to primary sources?