Why does one's heart beat fast as they run

Which of the following is a common response to cell signaling?

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

Describe the relationship and movement between temperature and density in a convection cell. make sure you identify the direction of travel