Â鶹´«Ã½

Your article on food advice was unintentionally very amusing ( 13 July, p 32 ). I have read Â鶹´«Ã½ from cover to cover since your first issue and have followed the changing, often conflicting, advice on food and nutrition. Since leaving boarding school, I have lived by the advice that "a little of what …

James Wong considers organic food only from the viewpoint that it is said to be more nutritious ( 6 July, p 22 ). But probably the most important motivator for its consumers is to avoid the pesticide residues that industrially farmed fruit and vegetables typically contain. I don't know of there yet being a requirement …

Over and over, we hear that one of the solutions to global warming is to plant trees ( 20 July, p 20 ). Certainly, these magnificent means of pulling carbon dioxide out of the atmosphere are an essential part of our response to climate change. But it is equally important to do something with the …

Electric cars are in the news again ( 13 July, p 18 ). Over the past few years, I have become concerned that people often treat battery-powered electric vehicles as a panacea. I see many problems with this. If demand for cobalt, nickel and lithium for batteries can be met, it will cause environmental damage …

Guy Cox suggests that the inability to make a decision proves free will exists (Letters, 6 July ). A deterministic decision-making process can find the weights of multiple options to be equal and so be unable to decide. It doesn't follow that because I can't decide whether to have an extra pint before I go …

You present a photograph of lions climbing trees in Lake Nakuru National Park in Kenya's Great Rift Valley and say that this is a relatively rare behaviour ( 6 July, p 26 ). I photographed lions doing this in Solio Ranch, Kenya, in 1995. The editor writes: This could be as a result of local …

Allow me to express my support for Feedback's comments on the metric system (Feedback, 22 June ). But though it was certainly developed in France, its roots lie with English bishop John Wilkins, who proposed a decimal system of measurement in 1668.

Michael Le Page reports that climate models may have missed major effects from clouds ( 2 March, p 10 ). Two more effects, which James Lovelock described in The Revenge of Gaia , are the effects of methane emitted from melting tundra and from underwater methane hydrate. Then there are the fires in Arctic forests …

I wonder why Ruth Searle writes of surprise that cat owners were found to be more adventurous and unconventional than dog people ( 6 July, p 43 ). Just last year, you reported that many cat owners are infected with Toxoplasma gondii , a parasite carried by cats that makes infected animals, including humans, more …

• Cold facts: An Arctic fox travelled 3506 kilometres during a 76-day polar marathon ( 6 July, p 16 ). • We're shaken: The epicentre of an earthquake is on Earth's surface above its focus ( 13 July, p 7 ).