Answer:
The plant produces seeds that are enclosed in fruits.
Explanation:
One possible observation that can make a scientist to effectively conclude that an unknown plant is an angiosperm is the possession of seeds which are enclosed in fruits.
Only gymnosperms and angiosperms produce seeds but while gymnosperms's seeds are bore in the form of naked cones, angiosperm's seeds are are enclosed in a fruit.
Every other group of plants that do not produce seeds belongs to one of ferns, bryophytes or algae.
