in the dark depths of the ocean, a female anglerfish extends a glowing ball from a modified spine to lure prey. The glow comes from symbiotic bacteria that give off light from certain chemical reactions. The anglerfish “lure” provides the bacteria with nutrients and a place to live. What type of interaction is this? Explain how each of these populations might be affected by a decline in the other population

if I am reading this correctly it would be Commensalism or parasitism

read what I put below for more information also ch.at noir? much approved I don't know if I saw it clearly since I only got a quick look at it

Explanation:

Commensalism  means when one species (the bacteria) is benefited which the other (the fish) is neither helped nor harmed

However if it is both being helped it would be Symbiosis because both parties are being benefited by the interaction

if it is only one party being helped in this interaction and the other party is being harmed this is called parasitism

mercury

explanation:

mercury is the least dense because of its size