What does this mathematical rebus means ?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

Christina is practising her dance steps along with her friends. In a particular sequence, all of them form a row. At that point, Niharika is standing in the 4th position from either end of the row.
Can you find out how many girls are practising together?

Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

It is an eleven letter word.
The first, second, third and fourth letters form a banquet's name.
The fifth, sixth and seventh letters form a car's name.
The eighth, ninth, tenth and eleventh letters form a mode of transport.

Can you identify what word it is?

Who always enjoys poor health?

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

Cristina was born in 1888. She just had her 30th birthday today how did that happen?

Which English verb becomes past tense just by rearranging the letters?

Which wheel of car does not rotate when you turn your car right?