What relationship could scientists track in order to see whether or not blue crabs were the main reason that large zebra mussels have declined? thank you will mark you brainliest

What characteristic of the basin that feeds the congo river system affects movement in central africa? a. the center of the basin is a dense rain forest. b. it is the center of ethnic conflict in the area. c. wildlife on the savanna makes it too dangerous to travel. d. the basin is surrounded by desert.