The phenomenon of uptake of water at expense of energy by the cell and usually against osmotic gradient is known as ……………………………………….

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes the uptake of water by cells, which requires energy and typically occurs against an osmotic gradient.

2. **Defining Osmotic Gradient**: An osmotic gradient refers to the difference in concentration of solutes (and consequently water) across a membrane. Water moves from areas of lower solute concentration (higher water concentration) to areas of higher solute concentration (lower water concentration) naturally.

3. **Energy Requirement**: When water is moved against this gradient (from lower to higher concentration of solutes), it requires energy. This energy is usually provided in the form of ATP (adenosine triphosphate).

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