Write the letter of the matching definition next to each term.
1. LIGHTNING
A. A rectangular area in a city surrounded by streets and usually containing several buildings (plural)
2. UNICELLULAR
B. Having or consisting of a single cell
3. FOSSIL
C. An oxide containing two atoms of oxygen in the molecule
4. ICECAPS
D. The place where something begins, where it springs into being
5. ORIGIN
E. A common nonmetallic element that is normally a colorless odorless tasteless inert diatomic gas
6. DIOXIDE
F. Water soaked soil
7. POLAR
G. Nutrient in meat and beans that builds muscle (plural)
8. ATMOSPHERE
H. An essential structural component of living cells and source of energy for animals (plural)
9. CARBOHYDRATES
I. Any division of quantity accepted as a standard of measurement or exchange (plural)
10. VOLCANIC
J. The act of conducting a controlled test or investigation (plural)
11. PROTEINS
K. Huge body of salt water (plural)
12. WATER
L. An abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous ___
13. CARBON
M. A living thing that has the ability to act or function independently (plural)
14. NITROGEN
N. Igneous rock produced by eruption and solidified on or near the earth's surface
15. EXPERIMENTS
O. A mass of ___ and snow that permanently covers a large area of land (plural)
16. ORGANISMS
P. What we eat to get energy and grow
17. ANCIENT
Q. Clear liquid we drink that falls as rain
18. CHEMICALS
R. The remains of a plant or animal that existed in a past geological age and that has been excavated
19. UNITS
S. Tiniest unit of living things
20. BLOCKS
T. Located at or near or coming from the earth's poles
21. CELL
U. Substance used in or made by chemistry (plural)
22. FOOD
V. Abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission
23. MUD
W. A very old person
24. OCEANS
X. Layer of air around the Earth