A forest ecosystem can support a limited number of bears. This is because...
Question 3 options:

bears hibernate during the winter.

the base of the food chain is seasonal.

available energy is lost from one trophic level to the next.

light that supports photosynthesis is limited during certain times of the year.

you can have just about every answer you can think of

the answer is c because it is most logical.

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.