How the universe was created:)
Limestone.
It is a sedimentary rock composed of calcite and aragonite. It is used as a building material mainly because it is easily available and easy to work with.
Limestone is used in the manufacture of steel as it is the primary raw material that helps to remove impurities from the iron ore and produces waste matter that has low melting point and viscosity
A DNA molecule consists of two strands of nucleotides twisted together to form a double helix. The sugar-phosphate backbone is found on the outside of this helix and the bases are found braching towards the middle. Hydrogen bonds join the thenitrogenous bases and hold the two strands together.
Therefore your answer is sugar and phosphate.
Answer:
Source of current, force and pathway.
Explanation:
Source of current, force and pathway are the three important things needed or responsible for the current flow. A supply of electric charges (electrons) which is provided by the electric source, force of push to move the charges through the circuit and a pathway on which current flows. Without these three things, flow of current is impossible. so we can say that the situation in which all these three things are present will allow the current to flow in the circuit.
I disagree because although recycling is good, Earth firstly is not a closed system and new matter enters the environment all the time, such as comets.