The right answer is Damselfish
The damselfish is a species of herbivorous fish that contributes to a balance of marine plants by eating algae among corals, to prevent the proliferation of algae and to promote the growth of coral reefs. The parrotfish (Scaridae) or "coral cleaner" has the same similarity of the diet with the same equilibrium that the damselfish offers, but it can also feed on coral.
Here's one I found interesting.
Can we ever beat photosynthesis?
-It’s one of the holy grails of energy; coming up with a material for capturing the energy of the sun which can beat the efficiency of photosynthesis. This is an incredibly challenging problem, to say the least. And it’s one that could have an outsize impact on our very way of life, leading to energy from water splitting and biomass from energy conversion.
If CO2 was in very small amounts then it would be the limiting factor of photosynthesis, this means the process will take place at a much slower rate because it is lacking one of the raw materials it needs for the process to occur. To find the optimum light intensity you really need all other factors to be at optimum levels or in abundance.
Cortex is the stores the food and water for roots
Orbits are the result of a perfect balance between the forward motion of a body in space, such as a planet or moon, and the pull of gravity on it from another body in space, such as a large planet or star. ... These forces of inertia and gravity have to be perfectly balanced for an orbit to happen.