Which two structures perform similar functions in cnidarians and sponges?

spicules in cnidarians and pores in sponges
tentacles in cnidarians and nerve cells in sponges
stinging cells in cnidarians and cilia in sponges
gut in cnidarians and collar cells in sponges

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint

answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.

those characteristics are cellular organization, reproduction, metabolism, homeostasis, heredity, response to stimuli, growth and development, and adaptation through evolution. some things, such as a virus, demonstrate only a few of these characteristics and are, therefore, not alive