What is the independent and dependent variable in this:
"sandy heard that plants compete for space. she decided to test this idea. she bought a mixture of flower seeds and some potting soil. into each of 4 plastic cups, she put the same amount of soil. in the first cup she planted 2 seeds, in the second cup she planted 4 seeds, in the third cup 8 seeds, and in the fourth cup 16 seeds. after 25 days she checked to see how many plants had grown and their height."

The correct answer will be- the number of seeds in cups.

Explanation:

The scientific experiments involve the parameters which directly controls and help determine the hypothesis. These parameters are known as the variables which could be changed or kept constant.

The variables which could be changed or manipulated by the researcher or can get a change on its own like time are known as the independent variables. The variables which depend on the independent variables and are to be studied are known as the dependent variable.

In the given question, sandy studied the growth pattern and height of the plant which are considered dependent variables but they changed the number of seeds in the cups and thus they will be considered as the independent variables.

Thus, the number of seeds in the experiment represents the independent variables.

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]