This week’s new questions

Check your subscription status, update your details and more. Why do humans enjoy black-and-white photos or videos, but have less tolerance for images that have only two other colours? If two chromosomes are better than one, why not three? **Why do humans enjoy black-and-white photos or videos, but have less tolerance for images that have only two other colours?** **If two chromosomes are better than one, why not three?

Wouldn’t this give you a better chance of surviving environmental change?** _Last Word is New Scientist’s long-running series in which readers give scientific answers to each other’s questions, ranging from the minutiae of everyday life to absurd astronomical hypotheticals. To answer a question or ask a new one, email [email protected]_ _To answer this question – or ask a new one – email [email protected]._ Receive a weekly dose of discovery in your inbox. We'll also keep you up to date with _New Scientist_ events and special offers. ### Twisteddoodles on life before the study began… Regulars ### Tom Gauld: DNA and fossil evidence proved they were close relatives Regulars #### Life ### Some of our favourite New Scientist Live moments – in photographs Regulars ### This El Niño will bring predictable disasters, so why aren’t we ready?

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