Pretty sure it’s hyperbole
What it means is that he wouldn't have been able to get where he got if it hadn't been for the scientific achievements of his predecessors. If it hadn't been for these "giants" that enabled him to see so far, he wouldn't have been able to make all the discoveries that he did. For those coming after him, he was a giant that enabled them, and so laws and theories and scientific knowledge always increases based on the knowledge before it.
Most men were angry because most of the think of women as workers and didnit like the idea of them in education at all.
Answer: The adjective clause modifies or describe the direct object.
Explanation: The adjective clause in the sentence astronomy is the direct object because the elected course the subject took was astronomy.