Answer: D
Explanation: Because the Gupta's developed the concept of zero, it helped mathematics greatly. By looking at the other side of the organizer, it looks like the impact of have the first efficient post office helped improve communication, so it would make sense that the invention of algebra helped develop pi.
Sonar uses sound to detect objects underwater. As well as using sonar, Ballard searched for the Titanic's trail of debris.
Explanation:
No duh, of course it is ! ! ! !
Without it, how are we supposed to go to collage and get a job?
Just think of the chain of reaction that will happen without school in a kids life.
