Intro to Chem help?

Question

1. A fragment of the DNA molecule has the base sequence tgac. what is the complimentary sequence

A. TGAC

B. GTCA

C. ACTG

D. CAGT

E. AGTC

2. What is the composition of crude oil?

A. Mostly saturated hydrocarbons having 5-12 carbons per molecule

B. Mostly saturated hydrocarbons having 12-20 carbons per molecule

C. Mostly aromatic hydrocarbons

D. Mostly hydrocarbons, but the precise composition varies widely depending on location

E. Mostly unsaturated hydrocarbons having 5-12 carbons per molecule

3. Which of the following statements is true of a radioactive tracer

I. Chemically, a radioactive tracer behaves like a nonradioactive isotope

II. A radioactive tracer is a very small amount of radioactive isotope added to a chemical, biological, or physical system to study the system

III. A radioactive tracer can be detected in exceedingly small amounts by measuring the radiations emitted

A. II only

B. I only

C. II and III

D. III only

E. I, II, and III

Answer 1

1. C. ACTG

2. D. Mostly hydrocarbons, but the precise composition varies widely depending on location

3. E. I, II, and III