Rough endoplasmic reticulum contains ribosomes, while smooth endoplasmic reticulum does not contain ribosomes. The ribosomes are what give rough endoplasmic reticulum its characteristic "roughness."
Choices 1, 2, and 3 all emit carbon dioxide, not enough to destroy the planet, but they still can cause it over a large amount of time, due to Carbon Dioxide being a greenhouse gas. Therefore, the answer is 4. Bicycles do NOT emit any carbon dioxide at all.
Answer: Catalase functions the best at the pH of 7 because the pH of 7 is not too acidic or alkaline. It is on the normal scale, like water. Catalase can't be placed in an acidic liquid. It can not be placed in an alkaline liquid either.
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