What best describes te change in salinity in an estuary at low tides as water leaves the area
A. salinity stays B. salinity increase C. salinity decrease D. salinity does not change regular patterns

During high tide when the level of seawater rises, more sea water is brought into the estuary. This makes the water very salty and thus increases the percentage of dissolved salt in the estuary. Therefore, at high tide, the salinity of an estuary increases significantly.

Explanation:

the value of the 4 in the hundreds place is 400 while the value of th e 4 in the tens place is 40

400 is way bigger than 40.