<span>The answer is d. front. A front is the narrow region between two air masses of different densities. The interaction of the air masses cause the mass that is less dense to rise. Once air rises it cools and condenses to form clouds and eventually leads to precipitation. Using cold fronts as an example, the denser mass of cold air forces the lighter warm air to rise. </span>
Answer:
because some chemical reactions release gases which may be odourless or may have smell, in order to identify it it is necessary to have a good sense of smell.
Used to show emotion and exciting phrases and exclamation
The nucleus is the control center of the cell. <span />
