Fresh water is any body of water with a low salt concentration. Organisms in fresh water various challenges which includes; Osmotic concentration such that fresh water is permanently dilute and most cells cannot function at this concentration of ions. Varying temperatures, variation in oxygen levels and reproduction and life cycle due to permanence of habitat and physiological difficulty of regulating osmotic concentration in larvae and juveniles.
Answer:
B
Explanation:
once neurotransmitters are released into the synaptic cleft, it binds to its receptors at the postsynaptic membrane. voltage gated calcium channels open and allows calcium to flow in, an action potential is generated immediately and reaches the end of the axon
Number 1: The Circulatory System is a vast network that contains organs and vessels.
number 2: Arteries have a thick wall which helps a powerful pressure from the heart.
number 3: Without the Circulatory System the body wouldn't be unable to maintain a internal environment.
number 4: The Circulatory and Respiratory system both have gas to help a or animal live in there internal environment.
number 5: Blood vessels brings oxygen to the tissues and absorbs carbon dioxide and other waste products to clear the lungs. And with out oxygen the tissues won't absorb carbon dioxide to clear out the lungs.
number 6: D
I believe it's aerobic exercise.
