Astar begins as a a large cloud of gas and dust.
a. nebula
c. dwarf
b. giant
d. black hole

a. nebula

A nebula is a large cloud that is formed by dust and gas present in space. Some of the nebulae may also form by the explosion of a dying star called as supernova. Also, some nebulae may prove as a precursor of new star formation. The gases which are responsible for the formation of nebulae are helium and hydrogen.  The dust and gases which forms the nebula are far but they are brought together as a single mass by the action of gravity. The clumps of gases and dust get bigger and the gravitational force acting on them also increases.

answer: the answer is a

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.