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the main producers in aquatic environments are
a.
phytoplankton
b.
zooplankton
c.
kelp
d.
fish

The correct answer for the blank is- a)  Phytoplankton.

Phytoplanktons are the autotrophic, microscopic organisms ( such as dinoflagellates, diatoms, blue-green algae) that are present in the aquatic enviornments ( both salty and freshwater).

They possess green pigment that is chlorophyll like green plants on land.

They are the main producers in the aquatic environments as they synthesize their own food through the process called photosynthesis, which is then consumed by other organisms ( such as zooplanktons) in the aquatic food chain. By doing so, they form the base of aquatic food chain.

youre right there are

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.