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 _______.

Option 2: universe; phenomena; application; exploration is the correct answer.

Let's read the passage with these words filled in:

"Achieving spaceflight enabled humans to begin to explore the solar system and the rest of the universe, to understand the many objects and phenomena 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 application of that understanding to serve human purposes — are elements of space exploration."

Each word fits naturally:

• Universe — refers to everything that exists in space, and "the rest of the universe" pairs perfectly with "the solar system."
• Phenomena — means events or things that are observed, which makes sense alongside "objects."
• Application — means putting something to use, which matches "to serve human purposes."
• Exploration — ties the whole passage together, as discovery, understanding, and applying knowledge are all parts of space exploration.

Why not the other options?

• Option 1: "Ideologies" (beliefs/ideas) has nothing to do with things observed from space, and "visualisation" doesn't describe the activity the passage is about.
• Option 3: "Cosmos" could work for the first blank, but "materials" is too narrow for what we observe from space, and "identification" doesn't capture the passage's meaning.
• Option 4: "Configuration" (arrangement/shape) makes no sense after "the rest of the," and "vastness" describes a size, not an activity.