Asunflower turns its head toward sunlight. what triggers this behavior in a sunflower? gravity phototropism presence of nutrients presence of water

Explanation:

Student A would be introducing more error. While student B is subtracting the actual filter paper used in the experiment, Student A is using the mass of a different filter paper, which may have a slightly different mass than the filter paper that was used. To avoid having to aacount for this, or introducing such an error, follow Student B in weighing the filter paper before adding the sand.

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