Which of the following is an example of commensalism?

D. A bird builds a nest in a tree

Explanation:

The action above is only benefitting thee bird but not the tree but at the same time it is not hurting the tree. This is an example of commensalism.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products

c: warm water flows from the western tropical pacific toward south america. that should be the right answer! hope it .