Answer:
They are not violent killers because they need their host to stay alive for their benefit And if the host dies the parasite wont have a host so they try to keep it alive for as long as possible.
Explanation:
Active transport is the homeostatic process that moves particles against a concentration gradient.
Parietal cells produce gastric acid (hydrochloric acid) in response to histamine (via H2 receptors), acetylcholine (M3 receptors) and gastrin (gastrin receptors). Parietal cells contain an extensive secretory network (called canaliculi) from which the HCl is secreted by active transport into the stomach.