Heart depending on what is counted as a chamber. The atrium and ventricle are sometimes considered "true chambers", while the others are considered "accessory chambers". Primitive fish have a four-chambered heart, but the chambers are arranged sequentially so that this primitive heart is quite unlike the four-chambered hearts of mammals and birds. The first chamber is the sinus venosus, which collects deoxygenated blood from the body through the hepatic and cardinal veins. From here, blood flows into the atrium and then to the powerful muscular ventricle where the main pumping action will take place. The fourth and final chamber is the
Which? trading businesses, for instance subscriptions to "Which?" magazine, which are donated to the campaigning part of the organisation to fund advocacy activity and inform the public about consumer issues. "Which?" magazine maintains its independence by not accepting advertising, and the organisation receives no government funding. The Consumers' Association is the largest consumer organisation in the UK, with over 573,000 subscribers to its magazine. Until 2006, the association used prize draws similar to those of "Reader's Digest" to attract subscribers, but following criticism they were discontinued. The Association now attracts subscribers to its publications with free mini-guides and trial offers. The