And explain how you know so i can try to understand !

A 1,3,2 B 5,4,6

Explanation:

The cell are placed in isotonic, hypotonic and hypertonic solutions respectively. Cells in isotonic remain the same since there is no net flow of water in any direction. Cells in hypotonic solution will take in water by osmosis, swell and burst. The osmotic pressure of the external solution is lower than that of the cell. This is called haemolysis. Cells placed in hypertonic solution will lose water by osmosis, shrink and the cell membrane becomes wrinkled.The osmotic pressure of the external solution is higher than that of the cell. This is known as laking or crenation.

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.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.