Which statements regarding hypotheses are true? Check all that apply.
Hypotheses are based on observations.
B. Hypotheses are written when experiments
are complete.
C. Hypotheses are formed from testable
questions.
D. Hypotheses are tested with controlled
Experiments

What are chlorofluorocarbons made of

The eruption of a nearby volcano causes a prairie ecosystem to receive a lot less sunlight. which of these is the most likely effect on the ecosystem? a-an increase in biodiversity. b-an increase in immigration to the area. c-a decrease in available water. d-a decrease in plant growth.

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?