Questions

For floating point numbers (float, double, long double) the values cannot be predicted exactly. Depending on the number of bytes, the precession with of the value represented varies. Float takes 4 bytes and long double takes 10 bytes. So float stores 0.9 with less precision than long double.

When atoi() tries to convert argv[0] to a number it cannot do so (argv[0] being a file name) and hence returns a zero.

The branch of biology that studies the different structures and functions of the cell is called Cell Biology or Cytology.

 
Cell biology (formerly called Cytology), is a Greek word: kytos, "vessel" is a branch of biology that studies the different structures and functions of the cell and focuses mainly on the idea of the cell as the basic unit of life.

The cell (from Latin cella, meaning "small room") is the basic

• Structural,

• Functional (and) 

• Biological unit of all known living organisms. 

A cell is the smallest unit of life that can replicate independently, and cells are often called the "building blocks of life". 

‘Suppose’ and ‘if’ both are used to guess, or think, or imagine something and both means the same thing. So, using them together is superfluous. So, ‘if’will be used.