Final answer:
Lakes and ponds (C) are the aquatic ecosystems where both littoral and benthic zones are most likely found, with the former being the shoreline area with sunlight and the latter the bottom part of the body of water.
Step-by-step explanation:
The aquatic ecosystems where both the littoral and benthic zones are most likely found are lakes and ponds (C). These zones are characterized by their specific locations and conditions within a body of water. The littoral zone is the nearshore area where sunlight can penetrate to the bottom, allowing a diverse array of plants and animals to thrive. The benthic zone refers to the bottom of the aquatic ecosystem, including the substrate (lake or pond bed), and is inhabited by organisms that either attach themselves to the bottom surfaces or live in the sediment.
In contrast, the open ocean (A) and deep sea (B) have well-defined zones like the pelagic and abyssal zones, but the littoral and benthic vernacular is less commonly applied. Rivers and streams (D) typically have a benthic zone but do not generally have a clearly defined littoral zone due to the continuous movement of water and lack of stable areas for plant growth.