The correct answer is: sea stars
All animals listed above are invertebrates. One of the characteristic of invertebrates are that they are protostomes with the exception of Echinodermata (sea stars). The difference between protostomes and deuterostomes is in their embryonic development (orgin of mouth and anus).
In protostomes the mouth forms first: the oral end of the animal develops from the first developmental opening. On the other hand in deuterostomes the first opening (the blastopore) becomes the anus, and the oral end of the develops from the second opening.
Humans are also deuterostomes.
Answer:
Density is a physical property of matter, as each element and compound has a unique density associated with it. Density defined in a qualitative manner as the measure of the relative "heaviness" of objects with a constant volume.
Seawater, water that makes up the oceans and seas, covering more than 70 percent of Earth's surface. Seawater is a complex mixture of 96.5 percent water, 2.5 percent salts, and smaller amounts of other substances, including dissolved inorganic and organic materials, particulates, and a few atmospheric gases.
The most abundant dissolved ions in seawater are sodium, chloride, magnesium, sulfate and calcium. Its osmolarity is about 1000 mOsm/l.
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An apple does hope this helps
