In muscle cells, myosin molecules continue moving along actin molecules as long as:

a. ADP is present and tropomyosin is released from intracellular stores.
b. ATP is present and troponin is not bound to Ca2+Ca2+.
c. ADP is present and the intracellular acetylcholine level is high.
d. ATP is present and the intracellular Ca2+Ca2+ concentration is high.

d. ATP is present and the intracellular Ca2+Ca2+ concentration is high.

Explanation:

Myosins are  motor proteins that plays a major role in  muscle contraction. They depend on ATP and responsible for motility in actin-based substances. Skeletal muscle is composed of myosin and actin fibers. Each myosin thick filament is surrounded by actin thin filaments, and each thin filament is surrounded by thick filaments. There exists a strong attraction between the myosin head and the myosin-binding site of actin which binds them spontaneously. This bond is aided by the presence of ATP and the high concentration of intracellular Ca2+. The myosin protein undergoes a change in its shape.

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.