I believe the answer is B, primary active transport. Root hair cells in plant use active transport to absorb mineral ions such as nitrates from the soil. The concentrations of minerals in the soil are lower in the soil than in within the root hair cell, therefore the transport will be against the concentration gradient which does not favor diffusion, therefore the pant has to use active transport.
<span>in an environment where there is little or no oxygen. aerobic respiration requires oxygen ad when it is not present fermentaion (anaerobic respiration) occurs because it works when oxygen isn't there</span>
The correct answer is A river water flowing into the sea
