The answer is A. V-shaped trench and B. A bioluminescent fish (apex)
The correct answer is a dichotomous key. Basically, you use the key to decide what species an organism is by looking at what traits it has, and if it doesn't have some traits you can instantly rule out a large number of species which brings you closer to your answer of what the species is that you're looking at.
Lyases
Lyases are class of enzymes that catalyzes reactions involving the formation of double bonds.
Lyases are class of enzymes that catalyzes the joining of C-C ( carbon to carbon), C-O (carbon to oxygen), and C-N (carbon to nitrogen) bonds by hydrolysis or oxidation. These bonds are usually held by the process of elimination which leads to the formation of new double bonds or cyclical molecules. Examples of lyases include; aldolase and adenylate cyclase.