Which best describes how the cardiovascular and respiratory systems work together? The respiratory system makes it possible for the cardiovascular system to make blood. The respiratory system feeds gases into the bloodstream to support the needs of the body. The respiratory system takes gases out of the blood so that no gases circulate in the body. The respiratory system helps the blood make its own gases from scratch.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."

answer; the code in musculoskeletal system subsection is associated with deep tissue possibly to the bone;

the answer is: the „power stroke“ step.

muscle contraction can be divided into a few steps:

1. the release of ach (acetylcholine) in the synaptic cleft, binding of ach for its receptor and consequently opening of the ca channels.

2. the release of ca, binding of ca for the troponin

3. troponin shifting the tropomyosin, which was blocking the active site on the actin

4. myosin heads attaching to actin by breaking down atp to adp+ pi

5.   formation of the ‘cross-bridge’ on the active site of the actin filament by myosin head

6. “power stroke” -the cross bridge pulls actin, which slides over the myosin

9.     7. the release of adp completes the cross-bridge movement and atp attaches to myosin, breaking the actin-myosin cross bridge.