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.
Platonic love in its modern popular sense is an affectionate relationship into which the sexual element does not enter, especially in cases where one might easily assume otherwise. A simple example of platonic relationships is a deep, non-sexual friendship between two heterosexual people of the opposite sexes.