Ok so theirs this thing called asking your teacher for help especially when it’s such an easy question
Answer:
A is the answer i think because it has more reef
A parasite moving between individuals other than parents and their offspring uses
horizontal transmission.
Horizontal transmission is the transmission of infections between (parasites) that are not in a parent-child relationship (vertical transmission). Horizontal transmission may include the carriers or <span>vectors which are other species. Transmission, in that case, occurs via the bite of the vector (an infected organism), like in malaria.</span>