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Item 3
What is another path carbon can take to enter ocean waters besides from the atmosphere?

Phytoplankton produce the majority of the oceans’ carbon dioxide.
Rivers pick up carbon from land and carry it to the oceans.
Rainfall carries carbon dioxide from the clouds.
Marine mammals produce most of the carbon dioxide when they breathe.

the answer is :

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.

the answer is false.. have a great day; )