The substance produced inside the leaf disks that caused them to float to the surface of the solution is
(1)ozone
(2)water
(3)oxygen
(4)nitrogen

When does dna replication(make a copy of itself)?

Why are scientists concerned about the depletion of the ozone levels in the stratosphere?

Cathy hypothesized that corn would not grow in mud. to test this hypothesis, she took corn kernels and placed 5 in mud, 3 in soil, and 2 in water. to her surprise, the kernels in the mud grew faster than the kernels in the soil. what error might have caused these unexpected results? a. wrong hypothesis b. not enough variables c. undefined control d. too many variables