As salinity increases:
density increases
electrical conductivity decreases
amount of salt (nacl) increases
all of the above

Option (d) is the correct answer.

Explanation:

The amount of salt present or dissolved in water or water body is known as salinity.

When salinity increases then number of particles increases, therefore, density will increase. Also, number of ions will decrease thus, electrical conductivity will decrease.

On the other hand, increase in salinity will increase the amount of salt (NaCl) is the water.

Thus, we can conclude that out of the given options, the option all of the above is true.

1. they vary with a higher number because boiling is way hotter than melting

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.