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Ethanol can be boiled safely.

Explanation:

Use a steam bath or hot plate, the ethanol can be boiled as long as you keep the vapors away from any ignition source. This can be done under a hood with a condenser in reasonable safety. Obviously, a steam bath is better.

for b, you will test two leaves, one from a plant kept in the light and one from a plant left in the dark. put the two leaves in boiling water to kill them. put the leaves in a boiling tube with ethanol. wait until all the green color disappears from the leaves. remove the leaves. wash the leaves.  spread the leaves out on a white tile. carefully add iodine to the leaves. the leaf exposed to light will turn blue black while the one in dark will remain colorless.

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave