Describe the symmetry in members of phylum echinodermata?

Bilateral Symmetry

Explanation:

Echinoderms evolved from bilateral symmetric species.

Even though adult echinoderms have five-sided or pentaradial symmetry, echinoderm larvae are ciliated, free-swimming species that form in bilateral symmetry making them look like embryonic chordats. Example of echinodermata is starfish.

Bilateal symmetry allows them to move anywhere in the water. That when a predator is trapped by 2 arms, the other arms can be used effectively by continuously placing pressure on the body part to pressurerise the animal to open.

Hence, phylum echinodermata have bilateral symmetry.

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.