Step-by-step Solution:

From the statement 'All roses are flowers,' we know that the set of roses is a subset of the set of flowers. The statement 'Some flowers are yellow' means there is an overlap between the set of flowers and the set of yellow things. However, this does not logically guarantee an overlap between the set of roses and the set of yellow things. The yellow flowers might not be roses. Therefore, no definite conclusion can be drawn. The question or options may be flawed, as none of the conclusions are logically certain.