Why are index fossils helpful? A. Since they are only from a specific time period, the rock layer they are found in, and all
fossils within it, must also be from that time period. This helps scientists date fossils.

b. They are the only radioactive fossils and so help scientists find its specific age

c. They never break down, like other fossils, so they are a permanent glimpse into
history.

The graph shows the amount of global warming happening in different ecosystems. which populations of organisms will likely decline the most as a result of climate change, and why? a.coral reefs because of the loss of the symbiotic algae living within their bodies b.penguin populations because the fish they eat will move into warmer waters c.mountain-dwelling birds because rising sea levels will relocate their food sources d.large cats in the rainforest because of decreased habitat loss for their prey