Answer:
The ovaries are small, oval-shaped glands that are located on either side of the uterus.
I would say energy myself, and this is because energy plays a key role in all of these. With trophic levels energy is being transferred amongst the levels. Food chain's is a map of how the energy is passed along the chain. Food web is a web of how energy is transferred, and this is why I would say energy is a keyword.
Answer:
Eugleas create their own food through photosnthsis, the process of absorbing sunlight to synthesize foods from carbon dioxide and water. An eyespot at the front end of the euglena detects light I belive
Explanation: