Which of the following is an example of a density-dependent factor that affects population growth in a terrestrial (land-based) system?

a. disease
b. the availability of oxygen
c. the amount of rainfall
d. the range of temperature
e. a hurricane

Example of a Density -dependent factor is Disease.

So option A is correct one.

Explanation:

Disease is more likely to break out and result in deaths when more individuals are living together in the same place. Parasites are also more likely to spread under these conditions

Disease is spread quickly through densely packed populations due to how close organisms are to one another. Populations that rarely come into contact with one another are less likely to share bacteria, viruses and fungi.

Much like the host-parasite relationship, it is beneficial to the disease not to kill off its host population because that makes it more difficult to for the disease to survive.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.