8. Insecticides are most likely to be damaging when used incorrectly.

True (see detailed explanation).

Explanation:

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In this case, since insecticides are substances that keep crops from insects that can eat or damage them, it has been acknowledged they are important for the agricultural industry and therefore the citizens sustainability.  

However, since insecticides have really complex chemical structures, they are unlikely or sluggishly decomposed by the humans and other animals' cells, which can lead to irreversible genetic damage, cancer and other serious diseases; therefore, when they are used incorrectly, say higher amounts than necessary, spread on crops that are not significantly affected by insects or by any other reason, they are very likely to be damaging for us, animals and in general the environment.

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(b) which contains higher levels of vitamin b, oranges or spinach?

explanation:

you can eliminate a, c, and d because they are questions based on opinions.