Final answer:
Option B) Parasitism is a symbiotic relationship where a parasite benefits at the expense of the host, weakening it without necessarily killing it immediately, to allow for the parasite's reproduction.
Step-by-step explanation:
Parasitism is a type of symbiotic relationship where a parasite species lives in or on a host organism, deriving its nutrients and causing harm to the host. The host is weakened as the parasite siphons off resources, impacting the host's ability to maintain itself. While parasites may eventually kill their hosts, they often have life cycles that are dependent on the host surviving long enough to allow the parasite to reproduce and spread to another host. Examples of parasites include roundworms in mammals and fleas that live on animals.