A population is all the organisms of the same species in a group, like humans. Population is different from a community in that a population is every organism of the species grouped as a whole, and a community is a certain number of organisms within the whole population. That may not make sense, but that’s as good as I can describe it.
If the bacteria has a capsule, it's more likely to be able to spread or cause a disease. The capsule greatens the chance, as its function is to protect the bacteria, as well as to keep it thriving and alive.
Active deffusion.. this way the water is retained and the unnecessary salts ions are expelled out.
Your answer would be D :)