> Examples of Obligatory Mutualism and Facultative Mutualism?

Examples of Obligatory Mutualism and Facultative Mutualism?

Posted at: 2014-11-15 
At least two examples of both please.

obligative mutualism: eukaryotic cells, yucca plants and moths

http://www.britannica.com/EBchecked/topi...

facultative mutualism: This is the more common type of mutualism exemplified by plants producing fruits eaten by birds while the birds help on dispersing the seeds of the fruit when they excrete them on places far from the parent plant.

http://www.biology-online.org/dictionary...

At least two examples of both please.