1. The origin and evolution of viruses is controversial. Discuss whether you think viruses evolved before the first cell or whether they have coevolved and are perhaps still coevolving with their hosts.

1. The origin and evolution of viruses is controversial. Discuss whether you think viruses evolved before the first cell or whether they have coevolved and are perhaps still coevolving with their hosts.

2.Very young children have a large pool of mature, naïve T and B cells but very few memory cells; elderly adults have just the opposite: very few mature, naïve T and B cells but many memory cells. Discuss how this affects the ability of young children and the elderly to respond to infectious agents.