Correct answer - potometer.
Why? - The potometer does not measure the rate of transpiration accurately because not all of the water that is taken by the plant is used for transpiration (water taken might be used for photosynthesis or by the cells to maintain turgidity). The potometer measures the rate of uptake of water.
A valley is the result of erosion by glaciers and flowing water
Rabbits produce large numbers of offspring during each reproductive season, yet the number of rabbits within a given population changes very little from year to year. The stability of the population size is most likely the result of environmental factors that keep the population in check (2). Rabbits are seen as food by many predators which will keep the numbers down. The principle of the survival of the fittest will ensure that young strong rabbits get to breed and carry the gene pool to the next generation.
With an insoluble outer layer which remains in the cell where it is formed until the energy is needed
