Option “4” is correct Deoxyribo nucleic acid (DNA) is a molecule that carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses.
392. The orange colour of carrot is because of –
1. It grows in the soil
2. Carotene
3. It is not exposed to sunlight.
4. The entire plant is orange in colour
Option “2” is correct The orange colour of carrot is because of Carotene.
393. Snake venom is highly modified saliva containing _________.
Option “3” is correct Snake venom is highly modified saliva containing zootoxins which facilitates the immobilization and digestion of prey, and defends against threats. It is injected by unique fangs after a bite, and some species are also able to spit.
Option “3” is correct Heavy water (D2O), also called deuterium oxide, water composed of deuterium, the hydrogen isotope with a mass double that of ordinary hydrogen, and oxygen.
395. Which of the following elements has the lowest melting point?
1. Bromine
2. Zinc
3. Lead
4. Calcium
Option “1” is correct Bromine has lowest melting point in the following.It has melting point of -7.2℃.
396. Ethane chemical formulae is _______________.
1. C2H6
2. C2H3oH
3. C2SHOH
4. None Of the above
Option “1” is correct Ethane has chemical formulae is C2H6.
397. Ethane chemical formulae is _______________.Which of the following bonds are weakest in nature?
1. Single bond
2. Double bond
3. Triple bond
4. Hydrogen bond
Option “4” is correct Hydrogen Bond is weakest bond between atoms.Occur in molecules that have covelent bonds. Sometimes the electrons are not equally shared; one atom tends to have an electron more often than the other atom. In this situation one atom of the molecule becomes partly negative and the other then becomes partly positive. This is especially common between water molecules.
398. In the following reaction, fill in the blank.
Acid + Base → _______ + Water
1. Carbon dioxide
2. Metal Oxide
3. Hydrogen Gas
4. Salt
Option “4” is correct When an acid and a base are placed together, they react to neutralize the acid and base properties, producing a salt. The H(+) cation of the acid combines with the OH(-) anion of the base to form water.
