Which step of a muscle contraction can be described as the longest sarcomere, where actin and myosin are the least overlapped?
step 1
step 2
step 3
step 4

Answer: Step 1

During step one no impulse has occurred yet. Thus, the muscle fiber is relaxed (at rest). The sarcomere is at its longest possible length due do the fact that myosin is not bound to the actin.

This step will end when the brain or spinal cord will send an impulse to the muscle. This will travel through the motor neuron and reach the neuromuscular junction. Here acetylcholine will be released, which in turn will trigger the impulse in the muscle.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.