Releases no sulfur when burned, has a higher net energy yield than other fossil fuels, and can be extracted and used without refining.

Natural Gas

Explanation:

Naturally occurring hydrocarbon gas are popularly referred to as natural gas or fossil gas. It components include majorly methane gas, other higher alkanes, little percentage of CO₂, N₂, H₂S (hydrogen sulfide) etc. They are produced as a result of exposure of  plant and animal matter to intense heat and pressure under the surface of the Earth over millions of years.When fossil gas/natural gas are burned, they release no sulphur content and there is usually a higher net energy yield than other fossil fuels.

Natural gas is a non-renewable hydrocarbon used as a source of energy such as electric generation, fuels for vehicles etc due to their higher net energy yield.

b. examine and describe cells

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.