B. Healthier ecosystems. If you're talking about benefits, this is the only positive on this list. The others are listing the difficulties or downsides.
Pick up after pets, plant trees, reduce plastic usage
I would say overproduction. Not sure though. Hope this helps!
The answer is B because:
Cell walls are made of cellulose and proteins (hence II).
Animal cells don't have cell walls (only cell membrane) but plant cells do so IV
They must be semipermeable since materials for example carbon dioxide and water for photosynthesis have to go into the cell <em>some</em> way.
Precipitation differences are the factor that does not contribute to "water stress" on the Earth.
<u>Explanation:</u>
- Less ocean water sources, population differences, Scarcity of economic water resources are the factor which leads to water stress on the Earth.
- Precipitation differences do not cause much difference in water stress. So it will not contribute to the water stress.
- An increase in population will cause major water stress because availability drinking water is less in the earth. Population increase can cause a major problem.