Composition of Earth's atmosphere by volume. The lower pie represents the trace gases that together compose about 0.038% of the atmosphere (0.043% with CO 2 at 2014 concentration). The numbers are from a variety of years (mainly 1987, with CO 2 and methane from 2009) and do not represent any single source.
Dominance and submission (also called D/s) is a set of behaviors, customs, and rituals involving the submission of one person to another in an erotic episode or lifestyle. It is a subset of BDSM. Physical contact is not necessary, and D/s can be conducted anonymously over the telephone, email, or other messaging systems.
Generally, an open relationship is when the parties involved have two or more romantic or sexual relationships occurring at the same time either as a short term relationship, such as dating, or long term relationship, such as marriage.