The energy required for muscle contraction comes from
a. atp.
b. ligaments.
c. oxygen.
d. chlorophyll.

The correct answer is A.

Muscles need energy to produce contractions. The energy is derived from ATP (which stands for adenosine triphosphate) that is present in muscle cells.

Muscles tend to contain only limited quantities of ATP. When depleted, ATP needs to be resynthesized from other sources namely creatine phosphate (CP) and muscle glycogen. Other supplies of glycogen are stored in the liver.  The body is also able to resynthesize ATP from lipids, i.e. free fatty acids.  Different sources of energy are used depending on intensity and duration  of the workload .

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prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.