In the tundra, life forms are limited by the interaction of several of Earth's spheres. One sphere that interacts with both the geosphere, hydrosphere, and biosphere is the cryosphere. What is this sphere responsible for in the tundra?
A) poor, rocky soil
B) low growing plants
C) ground permafrost
D) mountainous terrain

Select each correct answer. more than one answer may be correct. which of the following is a characteristic of unicellular organisms? they can possess tissues and organs. all of their functions are performed by a single cell. they are usually microscopic. each of their cells is specialized to perform a specific function.

Which of these conditions most likely produces an unstable isotope?

The comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is made to illustrate which of the following? a. that atoms are indivisible b. that atoms are very small c. that atoms are very large d. that in a copper penny, there is one atom for every person on earth