Question

why are merestmatic tissues are only present in plants? why can't animals live for 200 years?

Answer 1

Plants continue to grow throughout their life and in specific regions like root apex, shoot apex and cambium etc. Meristematic tissues are responsible for the growth in plants. On the other hand animal grow till a certain age, after that growth in animal ceases. So they don't need meristematic tissue for life long growth.
In animals the process of ageing is generally faster and the metabolism of animals gets slower with the age so they cannot live for 200 years like some trees.