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:
Cow's Milk
Explanation:
Basically, this is because babies really cannot digest cow's milk as they do with formula or breast milk.
The second trimester is when the respiratory system is mature.
Answer:
well you need to ask your teacher
Explanation:
