Which gas is released during photosynthesis?

Find the odd one out: 16, 25, 36, 48, 64

Find next in series: Z, W, S, N, ?

The human genome contains approximately how many genes?

Statements: All doctors are educated. Some educated are wealthy. All wealthy are successful. Some successful are happy. Conclusion I: Some doctors are happy. Conclusion II: Some educated are successful. Which is correct?

Complete analogy: Book is to Author as Painting is to ?