Answer:
Active transport
Step-by-step explanation:
The active transport of plants occurs with energy expenditure and, as in facilitated diffusion, occurs with the help of carrier proteins, which are called pumps. Unlike diffusion, however, transport occurs against the concentration gradient. That is, active transport allows molecules to be transported into and out of plant cells because of a difference in concentration of elements within and outside the cell.
An example of active transport can be seen in the question above, where the concentration of calcium in the root cells of certain plants is higher than in the surrounding soil, but through active transport calcium continues to enter the plant roots.