Question 86

A root hair cell is drawn as a long, narrow projection reaching out between the soil particles. What does that shape achieve?

It grips the soil so that the plant cannot be pulled up
It gives a much larger surface area for absorbing waterCorrect answer
It lets the cell reach light and photosynthesise underground
It stores spare water for the plant to draw on in a drought

Explanation

Stretching the cell into a thin projection greatly increases the area of membrane in contact with soil water, and how fast a cell can absorb depends directly on how much surface it presents. Gripping the soil is genuine work that a root does, but the root system as a whole does it, and a single hair-like cell is far too fine to hold anything in place.

Explanation

Continue with this test