A chemical leaks into a pond that selectively kills off the phytoplankton (a producer). Many of the other organisms in the pond die over a short period of weeks, and the overall species diversity declines. The phytoplankton in this pond could be considered a good example of .

1) A keystone species
2) An edge species
3) An indicator species
4) A core species
5) None of the above

Rick is a toddler with an easy temperament and active nature. people are often seen stopping to talk to him in supermarkets and parks where his mother takes him in the evenings because he smiles willingly at other children and adults. this aspect of rick’s behavior most likely reflects a(n) active genotype–environment interaction suppressive genotype-environment interaction passive genotype–environment interaction evocative genotype–environment interaction