Four common relationships between organisms are listed in the box. 1. Bees pollinate plants as they move from flower to
flower gathering nectar
2. Green algae grow on the backs of spider crabs living
in shallow water, camouflaging the spider crabs
while the crabs protect the algae from predators.
3. Fleas live on the skin of dogs and obtain nutrients
from the dogs' blood
4. Nitrogen-fixing bacteria obtain nutrients from their
host plants and use the nutrients to supply nitrogen
to the plants.
Which statements best describe these relationships?
A Relationships 1 and 4 are examples of mutualism.
Relationship 2 is an example of commensalism.
Relationship 3 is an example of parasitism.
B Relationships 1 and 2 are examples of commensalism.
Relationships 3 and 4 are examples of mutualism.
c Relationship 1 is an example of commensalism.
Relationships 2 and 4 are examples of mutualism.
Relationship 3 is an example of predation.
D Relationships 1, 2, and 4 are examples of mutualism.
Relationship 3 is an example of parasitism.