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>
Another name for cell cycle is called mitosis
Im not really sure about the water, other than the trees wouldn't be absorbing it so there would be extra? But a huge amount of trees like that produce a lot of oxygen, so there would not be less oxygen in the environment. Hope this helps!
Answer:
To study objects that are way too small