Answer:
<em>The correct option is d) an ecotone</em>
Explanation:
An ecotone can be described as an area of transition between two different biomes. An estuary can be described as an ecotone where the river water meets the seawater. The freshwater biome mixes with the seawater biome in an estuary. Unique plants and animals are grown in an estuary which are adapted to live in such an environment. The water present in an estuary is termed as brackish water. Hence, the correct option is d.
In photosynthesis experiment, the effect of the light will be observe during the starch production- thus you need to have a plant without a starch to observe if the starch is produced during photosynthesis. Letting the leaves of the plant deprived from light for 48 hours will be forced to use its reserved starch making the storage of the starch decrease.
I think it's D) atmospheric carbon dioxide.
Answer is that it’s a base