Energy is the currency of the cell, just like money is the currency of our society. Please compare the process of energy transfer in photosynthesis & cellular respiration with the process of money transfer through our banking system.

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers