Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): All vertebrates are chordates but all chordates are not vertebrates
Reason (R): Notochord is replaced by the vertebral column in the adult vertebrates.
In the light of the above statements, choose the most appropriate answer from the options given below:
| Class | Character | Example |
|---|---|---|
| 1) Xiphosura | Poisonous Claws | Limulus |
| 2) Arachnida | Coxal Glands | Scutigera |
| 3) Crustacea | Biramous appendage | Sarcoptes |
| 4) Diplopoda | Gnathochilarium | Spirostreptus |
If 0.01 mol of $\mathrm{P_4O_{10}}$ is removed from 0.1 mol, then the remaining molecules of $\mathrm{P_4O_{10}}$ will be:
An element has two isotopes having atomic masses 10 and 15 u, respectively. If the percent abundance of lighter isotopes is 80%, then the average atomic mass of the element is: