Questions

Mushrooms are heterotrophs. They are not plants or autotrophs.

Every living thing that exists need energy in order to live. This energy ultimately comes from the sun, and only plants, or autotrophs, can directly use this energy to make food. Those organisms that cannot harness the sun's energy are known as heterotrophs.

Mushrooms belong to kingdom Fungi and are heterotrophs because they decompose and consume nutrients from the soil. They are not green so they cannot photosynthesize

For this reason, mushrooms and all other fungi are heterotrophs.

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". 

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.