Use Models 1-4 to put the following events in order from the signal from the brain reaching a muscle to the contraction of the whole muscle. •Myosin bends in two places, releasing ADP and pulling on the thin filament.
•The nerve impulse reaches the end of the nerve and causes it to release acetylcholine (Ach)
•An electrical impulse travels down a nerve fiber
•The Z-lines are pulled closer together and the A-band shrinks
•Ach bonds to receptors on the muscle cell membrane and causes the electrical impulse to be transmitted to the muscle cell
•Calcium ions bind to troponin causing it to rotate
•The myofibril gets shorter (contracts)
•The electrical impulse inside the muscle cell causes the release of calcium ions from the endoplasmic reticulum
•Rotation of troponin move tropomyosin off of the myosin binding site on actin
•The myosin head binds the myosin binding domain of actin

the transfer of energy between two molecules spaced just nanometers apart plays a key role in many technologies, including photovoltaics, quantum information systems, lighting, and sensors, as well as in biophysics to measure nanometer distances and in photosynthesis. but an open question in this area is what effect, if any, the surrounding photonic environment has on this nanoscale energy transfer. by designing and performing a carefully controlled experiment to answer this question, scientists have settled the debate and found clues to improving the efficiency of many of the technologies that rely on this process.

explanation:

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.