A carbon atom has 6 protons and 6 electrons. Carbon has three naturally occurring isotopes, carbon-12, carbon-13, and carbon-14. Which of these statements is true about carbon and its isotopes? Hint: Think about what changes in an isotope. A. All carbon atoms have six neutrons.
B. All carbon atoms have six protons and six electrons.
C. Atoms of all carbon isotopes have either more than 6 electrons or fewer than 6 electrons.
D. Atoms of some naturally-occurring carbon isotopes may have twelve neutrons.

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.

9. the history of life on earth is recorded in

To be or not to be that is da question