Question

fill in the blank: __________ is a surface or layer of constant density. isohaline isotherm isopycnal isobar

Explanation:

An isopycnal is defined as a surface or layer of constant density. An isohaline is a line of equal salinity, an isotherm is a line of equal temperature, and an isobar is a line of equal pressure.

Answer:

C. Isopycnal