1 Match the topic sentences (1-3) to their supporting sentences (A-C). 1 It must be said, however, that there are many positive aspects to cycling to work. 2 However, genetically modified crops have their disadvantages. 3 There are many advantages to animal conservation programmes. A The main one is that they may have negative effects on people's health. В Firstly, they help save endangered species. С First of all, it is a cheap and easy way to stay fit and healthy.