Absence n. : A state of being absent or withdrawn from a place or from companionship; -- opposed to presence.

Absence n. : Want; destitution; withdrawal.

Absence n. : Inattention to things present; abstraction (of mind); as, absence of mind.

Example:
How would the Absence of root hairs affect a plant's ability to absorb water and nutrients?

Taxonomy
absence, Merriam-Webster Online Dictionary, Dictionary, webster, absence of mind, Word Games, Webster Online Dictionary with audio pronunciations, leave of absence, glossary, english, language, ESL, ab-s, 14th century, state of being, period of time, inattention, surroundings.

Defination from the web:
absence from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. ... 3 : want, lack <an absence of detail> 4 : inattention to present surroundings or occurrences <absence of mind> ...