21.   They feature Blue the cartoon dog and the genial human host, Steve, gently walking players through graphically simple but engaging activities.

22.   This protein fuses with human host cells.

23.   Better sanitation blockades the worst strains of cholera, which ride the water supply to find new human hosts.

24.   In effect, the immune system of the human host is tricked into identifying the pig organ as human.

25.   When a human host inhales C. pneumoniae, a sequence of events follow.

26.   The virus adapted to its human host and then spread through sexual contact, becoming the global pandemic that it is today.

27.   So for generations the dozens of apes which lope around Soko have enjoyed the hospitality of their human hosts.