Alvin is studying a model of the chemical structure of a common nucleic acid. He observes that the nucleic acid consists of four nitrogenous
bases: adenine (A), cytosine (C), guanine (G), and uracil (U).
Alvin's observation most strongly supports which of these conclusions?
A. The nucleic acid is a form of RNA, and is not DNA.
B. The nucleic acid is either mRNA or rRNA, but not tRNA.
C. The nucleic acid is either RNA or DNA.
D. The nucleic acid is DNA, and is not RNA.

Acar company is testing seatbelts using crash test dummies. the company finds that when cars come to a sudden stop, the crash test dummies' bodies continue to move forward. the seat belt keeps the crash test dummies from hitting the back of the seat in front of them. why do the crash test dummies' bodies continue to move forward even though the car stopped? a. the friction opposing their bodies' movement keeps them in motion. b. the inertia of their bodies keeps them in motion. c. the forward acceleration of the car keeps them in motion. d. the gravity pulling on the car keeps them in motion.

World class speed skaters can skate a 3,000-m course in about 4 minutes. what is their average speed for this course. a. 12.5m/s b. 1.33m/s c. 13.3m/s d. 1.25m/s

Which statements describe resources? one of the factors people use when deciding where they will live is the availability of resources. renewable resources have little value for people. resources are unevenly distributed throughout the world. energy is the world resource which has the highest use. the use of nonrenewable resources has decreased in recent history. the use of resources is evenly distributed throughout the world. the world's oil supply will last for the next forty years if its use continues as expected.