Can someone kindly tell me how i can answer questions 1, 5 and 6? :( I'm trying hard to search and understand but i can't seem to find the answers. thank you so much in advance.

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1 Answer
Apr 18, 2018

1) light
5) controlled variables
6) preparation of solutions can intentionally omit your target mineral

Explanation:

1) roots would not be exposed to light when in soil - black paper removes light

5) the weight, size and similarity of plants can be relatively well controlled - every experiment must control variable

6) you would prepare solutions in such a way as to add all critical salts but one (ie. not include potassium chloride as potassium is the absent element you were investigating in that sample)