Questions

In the early 1950s two scientists, Rosalind Franklin and Maurice Wilkins, studied DNA using x-rays. Franklin produced an x-ray photograph that allowed two other researchers, James Watson and Francis Crick to work out the 3D structure of DNA. The structure of DNA was found to be a double helix.

The troposphere is the lowest layer of the atmosphere and where most clouds are. That means all weather is in the troposphere. Almost all weather occurs in the Troposphere, basically, the lowest layer that goes up to about 10 - 15 kms.

P= I^2.R where, I= Current, P= Electric Power, R=Resistance. Here all the resistance is put in parallel combination and in parallel combination the value of Resistance decreases and dissipation of power increase, hence 3 times more power will be dissipated(3P).

When an atom loses an electron it becomes a positive ion by acquiring negatively charged. When it loses electron, the atom's radius also decreased.

Biological Control: This method is very effective. One pest is destroyed by another organism. For example the aphids are killed by lady beetle. The prickly pear is eradicted by cochineal insect. Here the advantage is, one does not use harmful chemicals which may get into the host plants.