Some resources require lengthy processing chains before being useful to the player.

However, the resources of Earth require more supplements as the global environment is slowly dying.

Since higher-level resources require a higher corresponding level, players are encouraged to trade amongst each other for resources.

The I-box then checks if the resources required by the two instructions are available during stage four.

Limited resources may require pressure to have fewer children.

First, it ignores the infrastructure necessary to support the trainer (let alone the training of trainers themselves) which doubles or triples the resources required.

Chemical and biological resources require a yellow or blue band, to warn people they're live, not training dummies.

Especially when limited space and resources require that we exclude many students whom we would like to admit.

"Limited resources require us to make choices every day," he said.

"Have you ever sat down and calculated how many resources your company requires to maintain this exorbitant lifestyle?"