Susan suffered from a heart attack. when the doctors tested the heart muscle, they found that she had an increased ratio of lactic acid to pyruvic acid in her heart. what does this say about the availability of oxygen in her heart muscle cells

Because of reduced blood supply

Explanation:

The normal heart has low pyruvic acid to lactic acid ratio which shows the heart is working properly and has no problem in it.

The heart with low pyruvic acid to lactic acid ratio shows that it has some respiratory problem and does not have adequate oxygen supply.

Even the person having  very low  pyruvic acid to lactic acid ratio shows respiratory problem.

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.