"the first fossil fuel to be used by man was oil which was followed by coal."

a. true
b. false

False. The first fossil fuel used by man is coal.

Explanation:

Fossil fuels are fuel formed from the remains of plants and animals or from natural processes. Fossil fuels are hydrocarbons, coals, oil and natural gas formed from natural processes. The first fossil fuel was coal and had been used as fuel since 1000BC. Fossil fuel are of great importance because the can be burn to produce energy.

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.  

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.'