Which of these is a biotic factor of an ecosystem?
a.
the temperature of water in a stream
b.
the bacteria that live in the intestine of a rabbit
c.
the amount of water vapor present in a rain forest
d.
the rocks that provide cover for a rattlesnake

I believe the correct answer from the choices listed above is option B. It is the bacteria that live in the intestine of a rabbit that is a biotic factor in an ecosystem. A biotic factor is any living component that affects the population of another organism, or the environment.

B. Weather.

Density-independent is usually something that affects the ecosystem no matter how much density, or how much population it has. Density-dependent is the opposite, the larger the density or population, the more damage it will cause. Disease, competition, and an abundant of food are all density-dependent things. If there is more population, disease will spread faster, competition begins with more density, and an abundant of food. Weather and climate changes, including natural disasters, are a prime example of a density-independent factor.