Which situation involves mainly biotic factors? * 1 point
A drought causes crops to die, and as a result cattle go hungry.
A fungus wipes out a bat population, which allows the mosquito population to
increase and spread disease to people.
A drop in the pH of ocean water prevents coral from growing properly, which harms
the coral reef ecosystem.
Dust from a volcanic eruption blocks sunlight to Earth's surface, and as a result the
weather gets colder.