A mature pollen grain contains two cells: the vegetative cell and generative cell. Vegetative cell is larger in size and has food reserve. The generative cell divides mitotically to give rise to the two male gametes before pollen grains are shed.

In Z scheme flow or non cyclic photophosphorylation there is constant flow of water is essential for electron supply. Both PSI and PSII should function jointly for smooth flow of electrons. 

In cyclic photophosphorylation electrons are derived from PSI and de energized electrons return back to PSI.

nitrification involves the oxidation of ammonia to nitrite by nitrococcus and later oxidation to nitrate by nitrobacter.

Phospholipases are enzymes needed for secretion of auxin at root apices.

Inductive effect decreases rapidly with distance, therefore, acidic strength decreases as the distance of EWG increases from carboxylic acid. Hence, 2-chloropropanoic acid is the most acidic among the given compounds.

Direct bonding of groups such as phenyl or vinyl to the carboxylic acid, increases the acidity of corresponding carboxylic acid. When the electronegativity of the carbon which is directly attached to –COOH group increases, the acidity of carboxylic acid also increases. 

E.N. in decreasing order is : sp> sp²> sp³ hybridised carbon. 

Hence decreasing order of acidity is- 

CH≡C-COOH> C₆H₅-COOH> CH₂═CH-COOH> CH₃-COOH

In benzoic acid –COOH is attached to sp² hybridised carbon atom of phenyl ring while it is attached to sp³ hybridised carbon atom of –CH₃ group. Formic acid does not have alkyl group, hence it is stronger acid than benzoic acid.

Generally the presence of an electron donating group decreases the acidity of carboxylic acid. Therefore, higher the number of electron donating groups present in the carboxylic acid molecule, lesser will be its acidic strength. Thus, the correct order of acidity is 

CH₃-COOH > CH₃-CH₂-COOH > (CH₃)₂-CH-COOH > (CH₃)₃-COOH

Use of SOCl₂ is preferred over the use of PCl₃ and PCl₅, because in this reaction the other two products obtained are gaseous i.e., SO₂and HCl, which escape itself from the container, leaving behind the acid halide.

Lenz’s Law corresponds to the law of conservation of energy. Induced EMF produces a current that opposes the change in flux, because the change in flux means a change in energy. Energy can enter or leave, but not instantaneously.