<span>The experimental evidence that leads </span><span>scientists to believe that only quantized electronic energy states exist in atoms </span>was the Niels Bohr experiment on Hydrogen gas. The quantized model for electron orbits in atoms that effectively explained the spectroscopic behavior of the atoms. Each line in the spectrum corresponds to one exact frequency of light emitted by the atom.
In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area that was previously occupied by living things is disturbed, then re-colonized following the disturbance.
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Take for example - you touching something sharp and instantly moving your hand away.
Sensory neurons in your fingers detect the external stimuli of the sharp object and send a nerve impulse to the spinal cord (does not reach brain) and is sent back to a motor neurone - attached to an effector that moves the muscle and moves the hand away. This is a rapid reflex action and involuntary.
Answer:
B) lighting a match
Explanation:
a chemical change is a chemical reaction involving the rearrangement of atoms. While a physical change can often be reversed, a chemically change typically cannot.
Always remember, if something is being lit on fire then it is a chemical change, since fire breaks the bonds in between the atoms.
Freezing water is a physical change because it can be reversed and does not alter the substance, which is water. a change in state i always a physical change
tearing up a piece of paper is a physical change since nothing on a molecular level has changed. its still paper.
Dissolving sugar in water is a <em>homogenous mixture</em>, meaning that it looks uniform without, however it is still only sugar and water, so it is a physical change.
