Scientists study bubbles trapped in ancient glacial ice to determine how concentrations of nitrogen and carbon dioxide gas have changed over time. However, bubbles in glacial ice cannot provide information about changes in phosphorus. Explain why air samples are not useful for this purpose, and propose an alternative method to study how the amount of phosphorus in a region has changed over time.

answeramino acids;

ans.

in united states (us), the first leading cause of death for both women and men is heart diseases that leads to more than half of the deaths. heart diseases develop due to narrow arteries, buildup of plaque in blood capillaries that arises difficulties in blood flow.

the second leading cause of deaths in us is cancer that affects individuals of all ages. it develops due to uncontrolled growth and spread of tumor cells, which results in death if the not controlled or treated.

the third leading cause of deaths in us is copd or chronic obstructive pulmonary disease. it includes difficulty in breathing, chest infections, and persistent cough. smocking is a leading cause of copd and around 80% of copd deaths occur due to smoking.

thus, the correct answer is 'option). cancer, copd, and heart disease.'