Questions

Water has the maximum density at 4oC. So at this temperature, it sinks down to bottom and stays here. If it cools further, it will become less dense and move up. So while the upper layers can cool enough to form ice, the bottom layers remain as water at  4oC .  

Therefore, (C) is correct.

For an atom to emit X-rays it should have difference in energy levels

Using automatically incrementing IDENTITY columns is very popular with database developers. You don’t need to explicitly calculate unique surrogate keys when inserting new data, the IDENTITY column functionality does that for you. The IDENTITY feature also allows you to specify useful Seed and Increment properties. When you use an INSERT statement to insert data into a table with an IDENTITY column defined, SQL Server will generate a new IDENTITY value.

You can use the @@IDENTITY variable and the SCOPE_IDENTITY and IDENT_CURRENT functions to return the last IDENTITY value that has been generated by SQL Server. This is very useful when you need to return the key for the row that has just been inserted, back to the caller.

Nitrogenous base: A molecule that contains nitrogen and has the chemical properties of a base.

DNA and RNA ::

The nitrogenous bases in DNA are

Adenine (A),

Guanine (G),

Thymine (T), and

Cytosine (C).

Whereas the nitrogenous bases in RNA are the same, with one exception:

Adenine (A),

Guanine (G),

Uracil (U), and

Cytosine (C).

Australia is the smallest of all the continents