Which of the following is true of environmental changes?
a. they cannot be caused by human activity.
b. they may affect several populations in an ecosystem.
c. they affect food chains, but not food webs.
d. they have no effect on living organisms in an ecosystem.

I think the correct answer from the choices listed above is option B. With regards to environmental changes, they may affect several populations in an ecosystem because it is where living organisms dwell and they try to adjust accordingly to these changes. Hope this answers the question.

Answer decreased soil salinity;

Ithink is a i believe