Which formula represents an acid?

A. CH4

B. HCl

C. NH3

D. PH3

The atmosphere is composed of A. the oceans B. the air within 500 feet of the Earth's surface C. all the gases that surround the Earth D. all the plants and animals that breathe the gases that surround the Earth.

The intervals of Earth's history are defined largely by their environmental conditions and the effects of those conditions on lifeforms. How do catastrophes relate to environmental conditions, lifeforms, and the intervals of Earth's history?

If the amount of gravitational force on an object changes, which of the following would also change?

A chemical reaction has not occurred if the products have

Many people claim that science is "just" based on theories, and that since theories can change, science shouldn't be considered stable. How could you prove that science is stable and valid?

O que sao ligações de hidrogênio?

What element has 6 protons and 8 neutrons?

If n = 2, what type of orbitals are possible? 1s, 2s, 2p, 3s, 3p, 3d

When a layer of air with temperatures above freezing sits above a layer of subfreezing air near the ground, which type of precipitation is likely to form? a. rain b. snow c. sleet d. hail

Which of these statements best explains how fossil records provide evidence to the scientific theory of evolution? A. They show how natural selection happened on Earth by chance. B.