2. the water on earth came from ancient a. Volcanic activity
b. Collisions with comets that contained ice
c. Both answers a and b
d. None of the above

3. How much of the earth’s water is held in the oceans?
a. 25%
b. 50%
c. 75%
d. Almost 100%

4. Which of the following is a solvent?
a. Rocks
b. Water
c. Ice
d. Steam

5. Water enters the ocean from
a. Rivers that empty into the ocean
b. Rain
c. Groundwater
d. All of the above

6. The major component of salt water is
a. Water
b. Salt
c. Other minerals
d. None of the above

What is a codon and where is it found

This is one form of rna that transports a specific amino acid to a ribosome during protein synthesis.

Use this dichotomous key for insect identification to identify the insect shown. 1. a. insect has one pair of wings. order diptera b. insect has two pairs of wings. go to #2 2. a. front wings thicker in texture than hind wings go to #3. b. front and hind wings are same texture throughout. go to #4 3. a. front wings are short order dermaptera b. front wings cover entire abdomen order coleoptera 4. a. wings with scale on all parts of their area. order lepidoptera b. wings without scales go to #5. 5. a. hind wings smaller than front wings. order ephemeroptera b. front and hind wings nearly equal in size. order odonata the insect pictured is in the order diptera. ephemeroptera. coleoptera. odonata.