What it 2 million converted to billion

Q. 1 billion = __________million.

Q. One billion is equivalent to 100 millions.

Q. The present world population is about
(a) 500 million
(b) 100 million
(c) 5 billion
(d) 7 billion

Q. The decay constant of ${}^{238}U$ is $1.54\times {10}^{-10}y{r}^{-1}$. What will be the average life of a sample of ${10}^{20}$ such ${}^{238}U$ nuclei?

Q. Total number of base pairs found in human genome is?