Astudent formulated a hypothesis that cotton will grow larger bolls ( pods ) if magnesium is added to the soil. the student has two experimental fields of cotton, one with magnesium and one without. which data should be collected to support this hypothesis?
(a) height of the cotton plants in both fields
(b) diameter of the cotton bolls in both fields
(c) length of the growing season in both fields
(d) color of the cotton bolls in both fields