Question

the acronym hippo is used to help us remember the reasons species become endangered and/or go extinct. what does the o in hippo stand for? oxygen overharvesting

Explanation:

The acronym HIPPO stands for Habitat Loss, Invasive Species, Pollution, Population (human), and Overharvesting (the "O"). Oxygen is not related to the reasons for species endangerment/extinction in this context. So the O in HIPPO stands for Overharvesting.

Answer:

Overharvesting (the option with "Overharvesting" text)