The sentences below have words that are missing. Choose the best option from those given below to complete the sentence.
Achieving spaceflight enabled humans to begin to explore the solar system and the rest of the _________, to understand the many objects and____________ that are better observed from a space perspective, and to use for human benefit the resources and attributes of the space environment. All of these activities - discovery, scientific understanding, and the __________ of that understanding to serve human purposes - are elements of space __________.