The optimum range for most crops growing in a soilless medium is _____________ -_____________ , because in this range micronutrients are _____________ enough to satisfy plant needs without becoming so _____________ as to be toxic)
a) 7.35, 7.45, soluble, soluble
b) 5.8, 6.4, soluble, soluble
c) 5.14, 5.75, insoluble, insoluble
d) 7.35, 7.45, insoluble, soluble
Answer: b) 5.8, 6.4, soluble, soluble