It is called a horizontal relationship
Answer:
D) four.
Explanation:
The two atria hold the blood that circulates away from the heart. The heart has four one-way valves, which open and close with each heartbeat. The tricuspid valve and the mitral valve are located between the atria and allow the blood to flow from the atria to the ventricles. Also you don't have to but mind marking Brainliest?
Answer: Parasites
Explanation:
Both tapeworms and lice depend on a living host to survive. The relationship between the parasite, tapeworm or lice, isn't mutual. The parasite only benefits from the relationship, because the host provides them with plenty of nutrients. In some cases, tapeworms and lice can carry diseases and infect the host. So, there is your answer and goodluck!
Bullying. also psychological abuse in some cases.