Select the correct answer from the drop-down menu. The earliest successfu I attempts to explore outer space involved square rockets Submit moon missions

Step 1: The earliest successful attempts to explore outer space involved $\square$.<br /><br />Answer: The earliest successful attempts to explore outer space involved **rockets**.<br /><br />Step 2: Select the correct answer from the drop-down menu.<br /><br />Answer: The earliest successful attempts to explore outer space involved **rockets**.