1.) For all of the above
2.) supplementary single-stranded ends.
3.) The strong negative charges from the phosphate groups in the DNA backbone cause it to migrate toward the positive pole.
I would say, C. Because an controlled variable is an experimental element which is constant and unchanged throughout the course of the investigation.
One way to protect the biodiversity of local forest ecosystems would be to prevent the logging or destruction of the fire by humans or also by natural disaster such as forest fires. Another way for forest ecosystems to be protected could be working to reduce pollution in nearby areas and also preventing the contamination of the water sources nearby.
Plants get nitrogen from the soil but it has to be turned into nitrates (by lighting or nitrogen fixation); this because nitrogen in the air is very unreactive, Then the animal eats the plant.
Bacteria can get nitrogen simply from the air
