Which of these best describes Earth's mantle?
Most dense layer, consists of the outer and inner parts
Thinnest under the oceans and thickest under continents
Middle layer, density increases with depth as pressure increases
Least dense layer overall, consists of two layers of different thickness

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