Answer: Base units
The principal SI units that are used to derive all other SI units are called base units. The base units are the units of fundamental quantities e.g. M L T that is Mass, Length, and Time. All other physical quantities can be written in the fundamental dimension forms. The physical quantities are not measured directly but are build up from the building blocks that are the fundamental quantities which have base units.
Answer : The partial pressure of 
is, 67.009 atm
Solution : Given,
Partial pressure of 
at equilibrium = 30.6 atm
Partial pressure of 
at equilibrium = 13.9 atm
Equilibrium constant = 
The given balanced equilibrium reaction is,
The expression of 
will be,
Now put all the values of partial pressure, we get
Therefore, the partial pressure of is, 67.009 atm
Index fossils are used to determine the relative ages of rock and fossils and are also used to define the boundaries between geologic periods.
<u>Option: A</u>
<u>Explanation:</u>
The fossils which are recognized as fossils guides or indicator fossils are used to classify and recognize geological or faunal periods, termed as index fossils. It must be of short vertical reach, wide geographic distribution and swift patterns in evolution. It helps to assess the rock layers ' age and helps to date other fossils found close and around them. For an instance, Ammonites were abundant in the Mesozoic period between 245 to 65 mya, they have not been found after the Cretaceous era, as they became endangered during the K-T extinction (65 mya).
The correct answers among all the other choices are D.) reflection from wet asphalt and E.) refraction from a water surface. These materials would result in horizontally polarized light. Thank you for posting your question. I hope this answer helped you. Let me know if you need more help.
Answer:
Distance =60m, Time = 6s, Speed = ?
Speed = distance/time
= 60/6
=10m/s
Explanation:
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