Questions

Electronegativity measures an element's ability to form chemical bonds. Helium is the most electronegative element followed by Fluorine.

Here in the given options, Oxygen is the most electronegative element. Fluorine is followed by Oxygen, Chlorine and Nitrogen is the most electronegative elements list.

Uracil is not found in DNA but found in RNA.

The process which wherein an Ecosystem may renew itself is known as Ecological Succession.

The time scale may be decades or a million of years after a mass extinction. 

It may be achieve over a period of time.

Regular dividend payments are signals that a company is healthy and profitable. Also, issuing dividends can attract investors (shareholders). Finally, a company may distribute earnings to shareholders if it lacks profitable investment opportunities.