B. Every ecosystem has weather
I suggest you watch the Amoeba Sisters video again, 1-2x and take notes.
Biomagnification is when toxins / heavy metal are present in small amounts in fish, but accumulate as you move into higher trophic levels. This is one reason why it can be toxic for humans to eat tertiary or quaternary consumers, such as swordfish, shark, etc.
Stressors may be natural in origin, being associated with such environmental influences as:
competition, predation, disease, and other interactions among organisms
constraints related to climate or to inadequate or excessive nutrients, moisture, or space
disturbances such as wildfire and windstorms
