Agricultural runoff can create NEC's (nutrient enrichment compounds). This can then impact water systems by creating smog.
forming acid rain.
changing the water flow
helping algae to overgrow.

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 statements correspond to cellular respiration? co2 diffuses passively into the cell. co2 diffuses passively out of the cell. co2 must be pumped out of the cell. o2 diffuses passively when produced inside the cell. o2 diffuses passively when converted to co2. o2 is pumped in and forces co2 out.

Which list is in order from simplest to most complex? a bacteria - virus - plant - protist b protist - bacteria - virus - plant c virus - bacteria - plant - protist d virus - bacteria - protist - plant