What is the main idea of this text? Before the invasion, scientists developed computer models to predict the effect of the zebra mussels. But they were still surprised by what happened. By 1992, there were so many zebra mussels, scientists estimate
they were filtering a volume of water equal to all of the water in the estuary every 1-4 days during the summer. In the years right after the invasion, phytoplankton fell by 80 percent. Zooplankton (which eat phytoplankton) declined by half. And the smallest zooplankton (called micro-zooplankton), fell by about 90 percent. By 1994, scientists hypothesized that zebra mussels were responsible for these changes. The mussels were filtering huge amounts of phytoplankton from the water. Less phytoplankton meant less food for zooplankton, so their numbers were shrinking too. Competition was taking place and the
zebra mussels seemed to be winning.
A. In the years right after the invasion, zebra mussels evolved and adapted to the Hudson River ecosystem.
B. In the years right after the invasion, zebra mussels caused a number of changes in the Hudson River ecosystem and food web.
C. In the years right after the invasion, zebra mussels did not have a major impact on the Hudson River ecosystem or food web.
D. At first, zebra mussels did not have any impact on the Hudson River ecosystem, but their impact increased over time.
please help me I will give out the brain thing and extra points.