Answer: 2. with two symmetrical shells - mirror images of each other.
the term "crinoid" means: 6. phylum where starfish and sea urchins belong
4. lived inside their shells: 1. exoskeletons are made up of this material
7. multicellular organisms that often live in colonies: 8. individuality of coral is called
Explanation:
Crinoid is a term that can be used to describe the radial symmetry of animals that have oral (side of mouth) and aboral surfaces (opposite to the mouth). It is characterized by the mouth at the top surface and surrounded by the arms for feeding it. This is a characteristic feature of animals like star fish and sea urchins and echinoderm animals.
The exoskeleton is a protective shell which protect the animal from the external environment like water, sunlight and predation.
The multicellular organisms that live in the colonies they form coral reef and individually the are called the coral polyp.
Iron III Chloride has a chemical formula of FeCl₃, while ammonium hydroxide has a chemical formula of NH₄OH.
The <em>balanced equation</em> would be:
FeCl₃ (aq) + 3 NH₄OH (aq) → Fe(OH)₃ (s) + 3 NH₄Cl (aq)
The precipitate is Fe(OH)₃ or iron iii hydroxide.
To find the <em>complete ionic equation</em>, dissociate the compounds in aqueous phases into their ionic forms:
Fe³⁺ + Cl⁻ + NH₄⁺ + 3 OH⁻ --> Fe(OH)₃(s) + NH₄⁺ + Cl⁻
To find the <em>net ionic equation</em>, cancel out like ions that appear both in the reactant and product side:
Fe³⁺ + 3 OH⁻ --> Fe(OH)₃
The Octet rule is a general rule of thumb that applies to most atoms. Basically, it states that every atom wants to have eight valence electrons in its outermost electron shell.
