An ecosystem is a biological community of interacting organisms and their physical environment. This includes both the biotic (living) and abiotic (non-living).

Force is applied to change an object's speed or direction of motion.

A neutron is a subatomic particle found in the nucleus of an atom. It is neutral as it carries no electric charge.

A substance undergoes a phase transition when it moves from one state of matter to another, for example, when water freezes or boils.

The Sun is a G-type main-sequence star (G2V) but is informally known as a yellow dwarf star. Composed of 73% hydrogen and 25% helium, the hot plasma that makes up the Sun reaches 9,900°F (5,505°C) at the surface. It formed approximately 4.6 billion years ago and makes up 99.86% of the mass in the solar system.