Questions

Free memory is maintained in linked lists, each of equal sized blocks. Any such block is of size 2^k. When some memory is required by a process, the block size of next higher order is chosen, and broken into two. Note that the two such pieces differ in address only in their kth bit. Such pieces are called buddies. When any used block is freed, the OS checks to see if its buddy is also free. If so, it is rejoined, and put into the original free-block linked-list.

Getting the value of an environment variable is done by using `getenv()’. Setting the value of an environment variable is done by using `putenv()’

Evaporation is the process that allows water to enter into the atmosphere.

Sunlight turns liquid water into water vapor which then rises higher into the atmosphere and forms into clouds.

Plants, too, help water get into the atmosphere through a process called transpiration.

Encoding refers to the getting information into memory.

Hydroelectricity is electricity produced from hydropower i.e, water.