What's the primary reason that mammals and avian dinosaurs thrived in the paleogene period? a. plants developed as the main food source for these heterotrophic organisms. b. their predators had been killed off by the permian extinction. c. their predators had been killed off by the cretaceous-paleogene extinction. d. the earth significantly warmed, and cold-blooded animals couldn't survive.

The correct answer is option B, that is, their predators had been killed off by the Permian extinction.

Explanation:

The avian dinosaurs and the mammals were small creatures, living under the pump of the dinosaurs that reign the world, however, also were ceasing the further enhancement in the development and the size of these species. At the termination of the Cretaceous era, due to the colliding of an asteroid on the Earth, all the dinosaurs got wiped out from the Earth's surface, with the only remaining one of the species of dinosaurs were the small avian species.  

Due to the opening of lots of niches, the avian dinosaurs and the mammals briskly began to diversify, evolve, and become much bigger in size. The mammals won the race for supremacy and they became the most prevailing species on the Earth.  

she forgot to record a transaction

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]