The proportion of dissolved substances in seawater is usually expressed in

a. parts per hundred.
b. parts per thousand.
c. parts per ten thousand.
d. parts per million.

i'm not sure if it's b or d, explain

Salutations!

The proportion of dissolved substances in seawater is usually expressed in

The proportion of dissolved substances in seawater is usually expressed in parts per thousand. Parts per thousand can also be called as salinity. Its expressed as parts per thousand because the proportion of dissolved substances in seawater is very limited.

Thus, your answer is option B.

Hope I helped :D

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Answer meranesia;