The answer is ring-like.
Clams have ganglia that form a ring around esophagus and that is why this network is called ring-like.
B. Krill
I hope this will help you that is the correct answer
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A microspheres is a microscopic hollow sphere, especially of a protein or synthetic polymer.
Answer:
The correct answer is - option C. 2 billion.
Explanation:
Cyanobacteria or BGA are microscopic organisms that live in water bodies normally and make their own food. These are unicellular organisms that have been around 3 and a half million years and consider as the first photosynthetic organisms responsible for the availability of oxygen on earth. These cells are also considered as the cell that evolved in the eukaryotic cells by differentiation around 2 billion years ago. The aggregated form of the cells are known as the mats.
