The key answer of exercise 4

Tracy

1. ✓ (a good idea - we don’t need as much space as we think we do)
2. ✗ (doesn’t think it will happen unless people are forced to do it)
3. ✗ (hard to imagine and won’t grow quickly enough)
4. ✓ (thinks it's already happening)
5. ✗ (hard to imagine - but you never know)

Stig

1. ✗ - (rich people will always be able to have big houses)
2. ✗ - (new fuels will have to be developed )
3. ✗
4. -
5. ✓ - (there are already some robots and this will be developed further)