a ) Fruits are a unique feature of angiosperms. After fertilization, an ovary of a flower becomes a fruit. Moreover, there are three types of fruits: simple fruits, aggregate fruits, and multiple fruits. In simple fruits, there is only one ovary. They may contain one or more seeds. ALSO, they may be fleshy or dry. Berry is a popular EXAMPLE for a simple fruit. Whereas, an aggregate fruit DEVELOPS from a single compound flower and contains many OVARIES. Blackberry is an example of aggregate fruits. On the other hand, multiple fruits are a result of multiple flowers with fused ovaries.seed :  Both angiosperms and gymnosperms produce seeds. Some seeds are naked while some are enclosed by fruits. Seed is the structure that develops from the fertilized ovule. The two integuments of the ovule become the two seed coats, which are outer seed coat (TESTA) and the inner seed coat (tegmen).----------------------------------------------------------------------------------------------------\