Along-term relationship between two species that usually involves an exchange of food or energy is
a. predation.
b. symbiosis.
c. niche.
d. competition.

The correct option is B) Symbiosis.

Symbiosis can be defined as a long term and a close biological interaction or relationship between two species, which involves the exchange of energy or food between them.

Niche is defined as the the position or ecological role played by an organism in a community of plants and animals.  It is determined by a set of environmental conditions, resources, and interactions it require.

On the other hand, Competition ( organisms compete for same environmental resources) and predation ( one population becomes the food resource for another population) are the other forms biological interactions.

i think its through the fallopian tube