What is a keystone species? 
A species that is very important to the health of a specific ecosystem

A species with a exterior shell such as turtle

A species that typically build its shelters out of a stone

A species which helps unlock new areas of an ecosystem by removing stones

Would really appreciate it, i have an idea but not completely sure

What element does susan b. anthony include in this passage to strengthen her argument?

Abiologist counts the number of rabbits in a population each year and observes a decrease in population. since the coyote population has exploded, the biologist concludes that the coyote population has had a negative interaction with the rabbit population. which describes the biologist’s actions? a.) experimentationb.) inferencec.) observationd.) interacting