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.
The mantle is made of a solid rocky substance.
It gets heavier and heavier because it is pressure that holds the earth together and keeps the core of earth a hot SOLID ball instead of liquid
Answer:
sun and electric heater
Explanation:
sun is the biggest source of heat energy
electric heater is also an example of heat energy as it warms us
