In each group of 4 letters, 1st and 3rd letters, 2nd and 4th letters alternatively increased.
Hence, the missing letter would be HL.
Farmer works in Land and Mason works in a Building.
A farmer's work is in land, cultivating crops.
A mason works in building construction, laying bricks and creating structures.
The flower is the odd one among the given things.
The flower is the only thing that is natural and is not made by man.
Poem, Novel, Painting, and Statue are the things that are made by man.
'Carpenter' makes a 'Chair' in the same way a Mason' builds a 'Wall'
"Wan" describes color, specifically a pale or sickly color.
"Insipid" describes flavour, specifically one that is bland or lacking taste
Bike uses petrol as fuel, while an electric vehicle uses electricity.
Electric vehicles operate on electricity.
Petrol-powered bikes which run on petrol.
Carpenter makes Furniture
similarly Mason builds a Wall
Aeroplanes are at the Airport and Boats are at the Harbour.
A harbour is a place where boats and ships dock for safety or to load and unload cargo or passengers.
Airports serve Aeroplanes.
Ignorant is antonym of scholar so lazy is antonym of hardworking