Compound are substances which can be formed by chemically combining two or more elements. Mixtures are substances that are formed by physically mixing two or more substances.
A gene is a basic unit of heredity and a sequence of nucleotides in DNA that encodes the synthesis of a gene product, either RNA or protein. For example, if both of your parents have green eyes, you might inherit the trait for green eyes from them.
Marijuana, LSD and club drugs are grouped together because THEY TEND TO BE TAKEN BY MIDDLE CLASS PEOPLE FOR RECREATIONAL USE.
The three drugs given above are put in the same group because they are used for similar purposes by similar group of people. They are psychoactive drugs which cause euphoria and make the users feel good. People who use this drugs are usually those in the middle class.<span />
Inner planets are terrestrial and outer planets are gas giants expected Pluto witch is a dwarf planet that isn't really a planet
