Read the text and fill in the gaps.
Scientists believe that rainforests 1____ be home to more than 10 million different forms of wildlife. The largest group 2______ of insects, which climb or fly easily from tree to tree. Most people are familiar 3_____ colourful parrots, but they are only one part of the total bird 4______, which goes from tiny hummingbirds to huge toucans. Many rainforest animals have developed for living in the treetops. Some monkeys have thin webs of skin between their legs that 5_____ them to almost fly between 6_______.
1 A may B can C should D would
2 A keeps B consists C holds D claims
3 A with B to C of D by
4 A set B company C population D society
5 A let B allow C make D admit
6 A branches B leaves C flowers D plants