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<\/figure>\n\nLETTER OF THE MONTH<\/span><\/p>\n\n I\u2019ve been watching David Attenborough\u2019s new series The Green Planet. <\/em>There was a plant that made its seeds the same size and appearance as antelope poo \u2013 it even smells like it! The plant has done this to fool dung beetles into taking the seeds and burying them, in order to give them the best chance of germinating, as the favourite food of dung beetles in the area is antelope poo. My first thought was: \u201cThat\u2019s amazing!\u201d However, my second thought was: \u201cBut how does the plant know what antelope poo looks or smells like?\u201d Then I must confess, my third thought was: \u201cI bet someone at BBC Science Focus <\/em>could tell me.\u201d So here I am. I\u2019m hoping that you can tell me as I\u2019m intrigued.<\/p>\n\n\n\n Kate Harris<\/strong><\/p>\n\n\n\n Thanks to evolution, the plant has developed the perfect cocktail of volatile chemicals to attract dung beetles. It didn\u2019t \u2018know\u2019 what the poo looked or smelled like, it merely developed its shape and aroma thanks to random genetic mutations taking place over thousands of years. Those seeds that successfully germinated after being taken by dung beetles were more likely to survive, and therefore passed their pong-producing genes onto their offspring. You can read more about species that look like faeces here: bit.ly\/poo_animals<\/a> <\/p>\n\n\n\n Alice Lipscombe-Southwell, <\/strong>managing editor<\/p>\n<\/div><\/section>\n\n The writer of next issue\u2019s Letter <\/em>Of <\/em>The <\/em>Month <\/em>wins an STM <\/strong>Myth <\/strong>18-litre <\/strong>rucksack. <\/strong>This durable, water-resistant bag is perfect for lugging your laptop from work to home, as it comes with a cable-routing system to let you charge on-the-go with cords out of site, and is designed to keep your laptop safe from any bumps. amazon.co.uk<\/a> <\/strong><\/p>\n\n There are several drawbacks to the idea that air taxis are about to take off in a big way (January issue). First, these flying machines require batteries to power their electric motors, so can supply and demand constraints limit their growth? Second, as the skies fill up with these machines, won\u2019t this just lead to congestion? Third, what about the increased risks of collisions as the skies fill up? Fourth, these machines are likely to be expensive, so it is only the rich who are likely to benefit. No, I suspect this is just another pie-in-the-sky idea.<\/p>\n\n Steve Jones<\/strong><\/span><\/p>\n\n We have heard so much from Dr Michael Mosley on his Just One Thing <\/em>podcast and in BBC Science Focus <\/em>about cold water being good for you (September issue). But how cold should the water be in the shower? Should the dial be turned all the way down, or be from the cold tap (surely that can\u2019t be good for you in winter)? Or should it be, as some doctors on the internet have said, just cold enough to be uncomfortable? They say 20\u00b0C or below constitutes a cold shower, and this is enough to feel the benefits.<\/span><\/p>\n\n Fred Isaac<\/strong><\/span><\/p>\n\n An interesting question to which, as far as I know, there is no answer. Personally, I start off with warm water, then switch to fully cold and stay there until my breath settles, which is normally less than a minute. A cold shower is below 21\u00b0C, and the water that comes out of your tap is probably going to be below 10\u00b0C.<\/p>\n\n Dr Michael Mosley<\/strong><\/p>\n\n We have been coincidentally signalling our presence to the Galaxy for approximately, the last 100 years, since we started radio communications. In order that we could communicate with other civilisations, it would take 50 years for our signals to arrive and another 50 years for us to receive their response. How many stars are there within 50 light-years of Earth who may have planets with the capacity to contact us?<\/span><\/p>\n\n Ian Hutt<\/strong><\/span><\/p>\n\n Stephen Kelly explained that the vast majority of human cells can\u2019t be frozen without irretrievable damage (New Year issue). So how can cryopreservation be used to preserve eggs and sperm?<\/p>\n\n Dr Richard Lindley<\/strong><\/span><\/p>\n\n To preserve eggs and sperm, the cells are mixed with a cryoprotectant solution to protect them from damage during freezing. The samples are then cooled and stored in liquid nitrogen.<\/p>\n\n Alice Lipscombe-Southwell,<\/strong> managing editor<\/p>\n\n Email<\/strong> \u2022 reply@sciencefocus.com<\/a><\/p>\n\n Post<\/strong> \u2022 BBC Science Focus<\/em><\/em>, Eagle House, Colston Avenue, Bristol, BS1 4ST<\/p>\n\n Twitter<\/strong> \u2022 @sciencefocus<\/a><\/p>\n\n Facebook<\/strong> \u2022 www.facebook.com\/sciencefocus<\/a><\/p>\n\nPeek-a-poo!<\/strong><\/h4>\n\n\n\n
WRITE IN AND WIN!<\/strong><\/h5>\n\n
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Pie in the sky?<\/strong><\/h4>\n\n
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Stay cool<\/strong><\/h4>\n\n
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Is anyone out there?<\/strong><\/h4>\n\n
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Quick, freeze!<\/strong><\/h4>\n\n
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