A)mitochondria and chloroplast:- converts energy,oxygen and carbon dioxide are involved in its processes.
B)mitocondria:- have fluids inside it
C)nucleus and ribosomes:- enclosed by two membranes
Atoms form new substances by sharing electrons with each other. the answer is most likely A.
The correct answer is gravity.
The planets and other heavenly bodies are attracted towards the earth by the earth's gravity. The pull which is formed by the gravity of earth holds the objects near the earth surfaces. The planets and atmosphere is also kept around the earth's surface by the gravity.
I THINK ITS B. HOPE I HELPED