<u>Answer:</u>
The principle of faunal succession state <em>"Specific groups of organisms have followed one another in a definite sequence through the Earth's history."</em>
<u>Explanation:</u>
Faunal succession basically means is that the fossils of the flora and fauna of different eras can be found in a specific order and never in the same strata. This allows the geologists to determine the time sequence and also to identify the various strata by dating the fossils that are found in each of them. The older version of fossils are found beneath the fossils of modified versions. For example fossils of simple feathers that cannot support flight are found to be succeeded by fossils of more complex feathers.
It’s because new discoveries are made all the time sometimes what was considered right may be found out to be wrong
Answer:
<h3>
Merits of modern periodic table:</h3>
- The wrong position of some elements like argon, potassium, cobalt and nickel due to atomic weights have been solved by arranging the elements in the order of increasing atomic number without changing their own places.
- The isotopes of some element have the same atomic numbers. Therefore, they find the same position in periodic table.
- It separates metals from non-metals.
- The groups of the table are divided into sub groups A and B due to their dissimilar properties which make the study of elements specific and easier.
- The representative and transition elements have been separated.
Hope this helps...
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They are called groups or family. Hope this helps
Answer: Option (C) is the correct answer.
Explanation:
Chemical formula of a secondary amide is R'-CONH-R, where R and R' can be same of different alkyl or aryl groups. Here, the hydrogen atom of amide is attached to more electronegative oxygen atom of the C=O group.
Therefore, the hydrogen atom will be more strongly held by the electronegative oxygen atom. As a result, there will be strongly hydrogen bonded in the liquid phase of secondary amide.
Whereas chemical formula of nitriles is RCN, ester is RCOOR' and acid chlorides are RCOCl. As no hydrogen bonding occurs in any of these compounds because hydrogen atom is not being attached to an electronegative atom.
Thus, we can conclude that secondary amides are strongly hydrogen bonded in the liquid phase.
