
1) Ability 2) Biology terminology 3) Not compulsory 4) Power
Found on
https://www.crosswordclues.com/clue/facultative

1) Enabling 2) Optional
Found on
https://www.crosswordclues.com/clue/facultative

Facultative means `optional` or `discretionary` (antonym obligate), used mainly in biology in phrases such as: ...
Found on
http://en.wikipedia.org/wiki/Facultative

of parasites, optional; compare obligate.
Found on
http://en.wikipedia.org/wiki/Glossary_of_botanical_terms

optional; incidental; conferring privilege
Found on
http://phrontistery.info/f.html

• (a.) Of such a character as to admit of existing under various forms or conditions, or of happening or not happening, or the like; • (a.) Having the power to live under different conditions; as, a facultative parasite, a plant which is normally saprophytic, but which may exist wholly or in part as a parasite; -- opposed to obligate. &bu...
Found on
http://thinkexist.com/dictionary/meaning/facultative/

having the power to live under different conditions either with or without oxygen.
Found on
http://www.chemicalglossary.net/definition/731-Facultative

capable of living in varying conditions. For example, facultative cleaners will feed on parasites but do not rely only them for food.
Found on
http://www.encyclo.co.uk/local/20126

Of parasites, optional. ... Compare: obligate. ... (09 Oct 1997) ...
Found on
http://www.encyclo.co.uk/local/20973

(fak´әl-ta″tiv) not obligatory; pertaining to or characterized by the ability to adjust to particular circumstances or to assume a particular role.
Found on
http://www.encyclo.co.uk/local/21001

The ability of an organism to grow either in the presence of absence of an environmental factor (e.g. facultative aerobe, facultative psychrophile).
Found on
http://www.encyclo.co.uk/visitor-contributions.php
Fac'ul·ta·tive adjective [ Latin
facultas ,
-atis , faculty: confer French
facultatif , German
fakultativ .]
1. Having relation to the grant or exercise faculty, or authority, privilege, license, or the like hence, optional; as,
facultative enactments, or t...
Found on
http://www.encyclo.co.uk/webster/F/2

Exhibiting an indicated lifestyle under some environmental conditions, but not under others.
Found on
http://www.geog.ubc.ca/biodiversity/efauna/InsectGlossary.html

having the power to live under different conditions either with or without oxygen.
Found on
http://www.hach.com/chemGlossary

Type: Term Pronunciation: fak′ŭl-tā′tiv Definitions: 1. Able to live under more than one specific set of environmental conditions; possessing an alternative pathway.
Found on
http://www.medilexicon.com/medicaldictionary.php?t=31842

Facultative: 1. In general, not obligatory but rather capable of adapting to different conditions. The opposite of facultative is obligate. 2. In bacteriology, bacteria that can grow under either aerobic or anaerobic circumstances (with or without oxygen).
Found on
http://www.medterms.com/script/main/art.asp?articlekey=31986

optional - occurs in some members in some years or situations. E.g., birds move different distances in different years depending on food variability.
Found on
http://www.sialis.org/glossary.htm

[
adj] - of or relating to the mental faculties 2. [adj] - (biology) able to exist under more than one set of conditions 3. [adj] - granting a privilege or permission or power to do or not do something 4. [adj] - not compulsory
Found on
http://www.webdictionary.co.uk/definition.php?query=facultative
adjective not compulsory; `facultative courses in the sciences`
Found on
https://www.encyclo.co.uk/local/20974

in general, not obligatory but rather capable of adapting to different conditions
Found on
https://www.encyclo.co.uk/local/22346
No exact match found.