Question

multiple select question
select all that apply
oceanographers express salinity as ______.
□ parts per thousand (ppt)
□ number of grains of salt per liter of water
□ grams of salt per kilogram of water

Explanation:

Salinity in oceanography is commonly expressed as parts per thousand (ppt), grams of salt per kilogram of water (which is equivalent to ppt in practical terms as 1 ppt = 1 gram of salt per kilogram of water), and sometimes also as the number of grams (or grains) of salt per liter of water can be a way to express it, but the standard and most common ones here are parts per thousand (ppt) and grams of salt per kilogram of water (since 1 ppt is 1 gram of salt per kilogram of water). Also, "number of grains of salt per liter of water" can be a way to express salinity too, though less standard than the first two. So we analyze each option:

• "parts per thousand (ppt)": This is a standard unit for salinity. Correct.
• "number of grains of salt per liter of water": This can be a way to express the amount of salt (salinity) in water. Correct.
• "grams of salt per kilogram of water": This is equivalent to ppt (1 gram per kg is 1 ppt), so it's a standard way. Correct.

Answer:

A. parts per thousand (ppt)
B. number of grains of salt per liter of water
C. grams of salt per kilogram of water