Question

Which explains how the actions of Bernardo de Gálvez affected British troops in Florida?

Answer 1

I believe the answer you're looking for is by opening a second front at Mobile, de Gálvez prevented the British from sending additional troops to Pensac.

Answer 2

On 14 March 1780, ending a month in campaign against the British, 2,000 soldiers commanded by Gálvez had captured Fort Charlotte in Mobile (Alabama). In 1781, General Gálvez hit the British again, taking 7,000 men against the British capital in Pensacola.  

The Siege of Pensacola was a battle fought early in 1781 in the context of the United States War of Independence. Spain, allied with the American rebels, waged a conflict to expand their colonial possessions in America, conquering territories belonging to Britain. On the way was the strategic city of Pensacola, in West Florida, which was taken from the British after a two-month siege.