What are the difficulties in measuring growth in a living organism?

Answer 1

Growth in organisms is basically defined as cell division before cells become specialised. Different parts of organisms grow at different rates and different times but growth can be measured as an increase in either wet mass, dry mass or height. Height and wet mass can be measured when an organism is alive, but dry mass can only be measured when an organism is dead, because then all the water can be removed. Despite this, dry mass is the best for giving a measure of growth.

Dry mass is often used because it eliminates the fluctuations that you get from using wet mass due to its water content. This is evident in weighing plants, since they have a high level composition of water and this water content depends on the amount of water in its environment so using dry weight tends to be more reliable in this case as it gives an idea of mass change.