The common name to the family member of phylum Echinodermata of marine family is echinoderm. They are usually characterized by a five-fold symmetry, and possess an internal skeleton of calcite plates. They are found at every ocean depth.
The features of all adult echinoderm are:
- They have a five-fold symmetry.
- Body without segmentation.
- Spiny skin.
- Internal skeleton.
- found at every ocean depth.
Answer:
Explanation:
The reasons that cities boomed during the Middle Ages are more employment opportunities, increased trade, and growing interest in culture and art.
The Arrhenius equation relates activation energy to reaction rates and temperature:
ln (k2 / k1) = (E / R) * (1/T1 - 1/T2), where E is activation energy of 272 kJ, R is the ideal gas constant (we use the units of 0.0083145 kJ/mol-K for consistency, to cancel out the kJ unit), we let T1 = 718 K and k1 = 2.30 x 10^-5, and T2 = 753 K and k2 be the unknown.
ln (k2 / 2.30x10^-5) = (272 kJ / 0.0083145 kJ/mol-K) * (1/718 - 1/753)
k2 = 1.91 x 10^-4 /s
Answer:
c. 
Explanation:
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Due to the fact that an odorless gas was released, the chemical reaction between lithium carbonate and a random acid (for instance hydrochloric acid) turns out into:
It is known that carbonic acid is unstable and it quickly decomposes into water and carbon dioxide which is an odorless gas. In spite of the fact that the 
releases 
it isn't the solid since that gas is odorous.
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