Answer:
An asteroid impact.
Explanation:
An asteroid impact is considered to have tossed rubble across the earth, killing off many species of plants and animals, 65 million years ago. Volcanic activity is involved in at least four mass extinctions, whereas an asteroid in just one.
Photochemical smog results from automobile pollutants reacting with ultraviolet light from the sun. <span>Nitrogen oxides released from the automobile are introduced into the atmosphere reacts with sunlight to produce singular oxygen atoms. Oxygen atoms then combine with molecular oxygen to produce ozone which is one of the components of photochemical smog.</span>
Answer:
you run the risk of crushing the objective lens onto the slides.
I'm sorry but can you be a bit more specific on these following observations?