In principle, if we could see all the way back in time we could see the big bang taking place. however, our view is blocked for times prior to about 380,000 years after the big bang. why?

Everything was too hot.

Explanation:

According to the Big Bang theory the entire universe existed in a dense singularity i.e., a location where the gravitational field is infinite. The material inside the singularity started to expand due to quantum fluctuations.

After the expansion stage had started everything was very hot and atoms could not form. But after this stage which was about 380,000 years after the Big Bang there was a cooling effect that photons could travel and reach our eyes.

i think the answer would be reserve.

answer a fan shaped mass of sediment deposited at the base of a mountain front do to an abrupt change in stream gradient;