Psychology Glossary. Genotype. The total set of genes contained within an organisms cells. Organisms contain some genes that are expressed (you can consider the expressed to mean that the gene is active or being used) and some that are not. Regardless, all the genes an organism has are considered the genotype.
Mars' closest approach to the Earth is called opposition, and occurs roughly every 780 days.
In 2003, Mars made its closest approach to Earth in nearly 60,000 years! It won't be that close again until the year 2287. When Mars and Earth are close to each other, Mars appears very bright in our sky.