In general, the most materially advanced and developed countries are focused on extensive development of the sector of their economy.
a. tertiary
b. secondary
c. primary
d. quaternary

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?

What are the pros and cons of quadrat sampling?

The law of thermodynamics states that energy can't be created or destroyed. to natural sources of energy on earth are the