Identify a probable reason that the dark moths survived while the light moths did not

During the industrial revolution, coal-burning discharged huge concentrations of smoke and smog into the nearby surroundings. This left a black soot layer on the once lighter-colored trees. The pollution also eradicated the light-colored lichens, which grew on the chunks of the trees. Due to this, the dark bark of the tree got exposed without the presence of lichens.  

Prior to the industrial revolution, the light peppered moth was common, while the dark one was rare. The light moths used to blend with the light-colored trees, which were covered by light-colored lichens. However, the industrial revolution modified the colors of the trees.  

As the trees got darker, light-colored moths were easy to identify and were hunted by birds at a greater rate, while the rare dark-colored moths mixed with perfection on the darker trees. This produced the dark-colored moths exhibiting a greater rate of survival. They lived longer and transmitted their dark-colored genes onto their young or offspring.  

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

explanation: