What was the South’s greatest concern when California applied for statehood?

The South feared it would lose power and influence in the Senate.

Explanation:

if california became a separate state they could choose to be free or slave and they would choose free which would make the free and slave states unequal in the senate and they could lose power and votes which could mean they could vote to make the south free too.

very positive impact on our industries in the west, sine they promoted settlement and increased the ways in which goods could be transported to market.