Jars "A", "B" and "D" are necessary to answer the question. If sunlight and oxygen are both necessary for growth then the plants in jar "A" will grow. The plants in jar "B" will die because there is no oxygen while the plants in jar "D" will also die because there is no sunlight, if both sunlight and oxygen are necessary. The results from jar "C" are not critical because if the plants die we are not to know the reason. Is it from lack of sunshine or oxygen?
The variables are:
temperature
of the air in the jar;
amount of water and soil in each jar;
type of jar;
size and type of plants.
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Experimental technique Controlled experiments Plants, oxygen and sunlight |
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It was suggested to Jonathon that plants require sunlight and oxygen to grow. In order to test this Jonathon set up 4 glass jars as shown below. |
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Which three jars are necessary to answer the question, "Do plants need sunlight and oxygen in order to grow?"
Solution |
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Continue
with another experiment |
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