Which of the following is $NOT$ a characteristic of the phylum $Annelida$?

$A$ geostationary satellite is revolving around the earth. To make it escape from the gravitational field of the earth,its velocity must be increased by ........ $\%$

$A$ police party is moving in a jeep at a constant speed $v$. They see a thief at a distance $x$ on a motorcycle which is at rest. The moment the police see the thief,the thief starts moving with a constant acceleration $a$. Which of the following relations is true if the police are able to catch the thief?

The dental formula of a rabbit is .......

$A$ coin is tossed $n$ times. The probability of getting a head at least once is greater than $0.8$. Then,the least value of such $n$ is:

Anhydrous $Na_2CO_3$ is also known as