Aphids eat plant sap, and they excrete honeydew that ants can use as one source of food. Ants have been observed protecting aphids from predation by ladybugs. This is most likely an example of: a) Facultative mutualism b) Obligate mutualism c) Ectoparasitism d) Endoparasitism e) Commensalism

Ectoparasitism. (Ans D)

Explanation:

Parasitism is a type of relationship which is found between two species where 1 species, the parasite, gains benefits that come from the expense of the host species. Ectoparasitism is one of the examples of parasitism.

Ecto-parasitism: It is defined as a relationship where the parasite lives in the skin of the host, not within the body of the host. In this parasitism, the relationship between a host and parasite is non-mutual. In this parasitism, Ants are benefiting and aphids are being harmed.