Can someone help me plz?

The development of new inventions in the field of space travel seemed rapid. how does the word rapid function in a sentence?

The pizza delivery boy was neither early nor late he was right on time. question 12 options: (a)correct as it is (b)the pizza delivery boy was neither early nor late, he was right on time. (c)the pizza delivery boy was neither early nor late; and he was right on time. (d)the pizza delivery boy was neither early nor late: he was right on time.

Nsilent spring rachel carson makes up a fictional story about what life in the united states will be like if we don't save the environment, whereas in "save the redwoods" john muir?