Cold air falls because a. its's icy
b. it's more dense than warm air
c. it's heavier than warm air
d. It's less dense tha warm air

Which best describes a benefit of using dna technology in medicine? a) medicine can be produced in mass quantities. b) medicine can be distributed at a reduced cost. c) medicines have fewer side effects. d) medicines are resistant to antibiotics.

Match each description with the correct form of energy. 1. energy of an object's position above the ground. 2. stored in the bonds of atoms and molecules 3. stored in the nucleus of an atom 4. energy of vibrating molecules 5. movement of objects used to do work 6. created by vibrations in electric and magnetic fields chemical energy mechanical energy heat gravitational energy light nuclear energy

What is a quantitative observation? a. an observation that proves the hypothesis is wrong. b. an observation about the number or amount of something. c. an observation about the color, shape, size, or condition of something. d. an observation in which the appearance of something is described using descriptive language.