Natural radiation occurs in elements that have more neutrons than protons because those elements tend to be

Imagine that you have produced several versions of lactase, each of which differs from normal lactase by a single amino acid. describe a test that could indirectly determine which of the versions significantly alters the three-dimensional shape of the lactase protein.

The tilt of the earth's axis of rotation is responsible for the a) ocean's tides. b) size of the moon. c) brightness of stars. d) earth’s seasons.

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains