1. One of the best places to find sponges is along the edge of the continent, in . 2. Sponges are , undoubtedly the simplest and most primitive on earth. 3. Porifera

fresh-water, salt-water

Animals

Explanation:

Sponges are the simplest and most primitive animals on earth. They are found in continental water bodies, where 98% of the population are found in salt-water and the remainder in fresh-water.

They have little or no defined organs and movement is hardly noticed in adult sponges, feed by filtration, and have a rather flexible skeletal structure.

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