)a third population of crayfish lives in a very muddy stream. like the cave form, these crayfish have longer antennae, but unlike the cave form, these muddy stream-dwelling crayfish have retained their eyes. of the following hypotheses, which best explains how crayfish in the muddy stream have long antennae? a. among crayfish in the muddy stream, those with sense1 had greater reproductive success than those without sense1. b. in many crayfish individuals in the muddy stream, a mutation occurred that increased the length of antennae, but did not increase the activity of sense1. c. crayfish in the muddy stream are more closely related to the cave crayfish than they are to the surface crayfish. d. among crayfish in the muddy stream, those that possessed a mutation that increased the length of antennae, but not the activity of sense1, had greater reproductive success.

a fossil fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms, containing energy originating in ancient photosynthesis.[1] the age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years.[2] fossil fuels contain high percentages of carbon and include petroleum, coal, and natural gas.[3] other commonly used derivatives include kerosene and propane. fossil fuels range from volatile materials with low carbon to hydrogen ratios like methane, to liquids like petroleum, to nonvolatile materials composed of almost pure carbon, like anthracite coal. methane can be found in hydrocarbon fields either alone, associated with oil, or in the form of methane clathrates.

the theory that fossil fuels formed from the fossilized remains of dead plants by exposure to heat and pressure in the earth's crust over millions of years was first introduced by andreas libavius "in his 1597 alchemia [alchymia]" and later by mikhail lomonosov "as early as 1757 and certainly by 1763".[4] the first use of the term "fossil fuel" was by the german chemist caspar neumann, in english translation in 1759.[5]

in 2017 the world's primary energy sources consisted of petroleum (34%), coal (28%), natural gas (23%), amounting to an 85% share for fossil fuels in primary energy consumption in the world.[6] non-fossil sources in 2006 included nuclear (8.5%), hydroelectric (6.3%), and others (geothermal, solar, tidal, wind, wood, waste) amounting to 0.9%.[7] world energy consumption was growing at about 2.3% per year. in 2015 about 18% of worldwide consumption was from renewable sources.[8]