Aplant with blue flowers is crossed with a plant with yellow flowers. some of the offspring have green flowers. this is an example of a.)multiple genes b.)incomplete dominance c.)complete dominance

Option B, incomplete dominance

Explanation:

In incomplete dominance, the two alleles that pair up to express a trait restricts the sole expression of characteristics associated with individual allele. Thus the offspring’s produced have completely different characteristics/trait as compared to the paired parent's allele’s characteristics/trait.

Here in this case neither the blue nor the yellow color of the flower expresses themselves completely thereby producing entirely different color flowers i.e green flowers.

A very common example of incomplete  dominance is production of pink flowers when white and red flowers are crossed.  

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