The answer is C. Organelles
Atoms bound together and form molecules. Molecules are a little more complex than atoms. For example water is composed of two hydrogen atoms and one oxygen atom which are both gases. Properties of oxygen and hydrogen are completely different than water molecules.
using seeds from the same source.
using the same kind of soil for both groups.
giving the control and experimental groups the same volume of water.
keeping the light the same for the experimental and control groups.
measuring plant height the same way and at the same time for both groups.
The four mechanisms are as follows:
1) Orographic lifting: Air is forced to rise over a mountainous barrier
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2) Frontal wedging: Warmer, less dense air is forced over cooler, denser air along a front
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<span>3) Convergence: Pileup of horizontal air flow resulting in an upward flow
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<span>4) Localized convective lifting: Unequal surface heating causes localized pockets of air to rise because of their buoyancy. </span><span />
The answer is C. It eliminates the toxic chemical problem. Hope this helps!