Which of the following is not required for the translocation of sugars through phloem?
a) sugars are loaded at a "source" such as leaves.
b) sugars are unloaded at a "sink" such as the root.
c) atp.
d) evaporative pressure.

The correct answer will be option D.

Explanation:

The transport of photosynthates takes place through the tissue phloem.

The site at which the sugar is produced is known as the source while the site at which it is required is known as the sink.  The sugars are translocated through the pressure-flow model which states that sugar is transported in phloem sieve tube elements with the help of turgor pressure and no evaporative pressure is involved in the translocation of sucrose from source to sink.

Thus, option D is the correct answer.

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.