Explain the relationship between crossing over
and genetic variation.

There is direct relationship between genetic variation and crossing over.

Explanation: Crossing over is the main cause of genetic variation because in crossing over, parts of chromosomes are exchanged between two different chromatids in the process of gametes production. These chromatids are different from the parent chromosomes so variation occurs in the genetic makeup of living organisms due to crossing over.

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.