Answer :

Building smaller houses

Having more GMOs so food has more production

Build more houses on abandoned/unclaimed land

The answers are:

- Building smaller houses and focus on vertical building; building small and practical houses and focusing on vertical building are essential because on a smaller space there can be accomodated much more people.

- Building homes on abandoned unclaimed land; there's lots of acres of land that is just left to be even though it is not owned by anyone, so using this land for making houses and flats is of great importance for rational and practical usage of the land for accommodation of large number of people.

- Increase the GMO's so that there's bigger food production for smaller price; GMO's are known to give much more than the natural plants and they are also much less demanding in conditions for production and expenditure, so they can solve a big portion of the food scarcity problem.