A 28-year-old female presents with severe chest pain and shortness of breath. She is diagnosed with pulmonary embolism, which most likely originated from the:
a. Left ventricle
b. Systemic arteries
c. Deep veins of the leg
d. Superficial veins of the arm

C. Deep veins of the leg

Explanation: Pulmonary embolism is a health condition which is mostly caused by deep veins of the Leg containing blood clots in a medical situation called (DEEP VEIN THROMBOSIS) that finds their way up to the arteries.This clot bloods will cause the arteries to get blocked leading to SEVERE CHEST PAIN,SHORTNESS OF BREATHE etc, this medical situation is serious and life threatening capable of leading to Death.

pulmonary embolism,

This is the blockade(embolism) of the lungs arteries by substances (embolus)usually blood clot (thrombus)from the leg   transported in the bloodstream  to reach the  lungs through  the heart. it cut blood ; oxygen, nutrient supply to the region where the blocked vessels supplies  and therefore may lead to damage and  death of the  part.

The blockade materials (embolus) may be , air  bubbles ,  fat globules or a foreign substances.

individuals who smokes,  those that are inactive, suffering from cancer , from stroke, those that  take progesterone  drugs   are susceptible to this condition.Thus it a condition that arises from the complication of a diseases, and not a disease on its own.

Coughing of blood, shortness of breath, rapid breathing,paleness of skin,fainting  are common symptoms of this condition,

Chest X-ray , ECG are among method of diagnosis.

Treatments involved use of anticoagulants to reduce blood viscosity, to ensure easy  flow, surgery are among methods of cure..

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.

the answer is:

carbon dioxide