Questions

Nuclear power energy source generates radioactive waste.

Ctrl+Shift+F Opens the Font dialog box with the focus at the Font combo box.

Gene is a hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic in an organism.

In short it is a piece or segment of chromosome.

Genes undergo mutation when their DNA sequence changes. 

The classical orchestra uses violin, flute, clarinet, cello, piccolo, Bass,...

For neutral atoms, the periodic trends in atomic size can be described like this

Atomic size decreases when going from left to right across a period,
Atomic size increases when going from top to bottom down a group.

Let's use these trends to try and figure out which atom would have the largest radius.

If you look at elements that are located in the same group, potassium will have a larger atomic radius when compared with sodium. Likewise, bromine will have a larger atomic radius when compared with chlorine.

Now focus on potassium and bromine. Since potassium is located at the start of period 3, and bromine at the end of the same period, potassium will have a larger atomic radius than bromine, and thus the largest atomic radius of the four given atoms.

In 1952, Waksman was awarded the Nobel Prize in Physiology or Medicine in recognition "for his discovery of streptomycin," the first antibiotic active against tuberculosis.