Question

how have changes in seatbelts kept people safer? fill in the blanks to explain.
at first, seatbelts went across the
shoulder
chest
lap
only. then
seatbelts were
, every seat
have this kind of
seatbelt.
by 1975 a law required that three - point seatbelts be put in the front seat of all new cars. after more studies, another law passed in 1985, and the belts were required in the back seat, too. these are the type of seatbelts you see

Explanation:

The first blank is about the initial part of the body seatbelts went across. Lap - seatbelts were the first type. Then, three - point seatbelts (which go across the shoulder and lap) became common. And by 1985, laws required them in the back seat too.

Answer:

At first, seatbelts went across the lap only. Then three - point seatbelts were required. By 1985, every seat was required to have this kind of seatbelt.