Activation energy is required to start a chemical reaction. Activation energy is the energy needed to allow the reactant to react. Activation energy is measured in Joules (J).
Endocrine gland - a group of cells that secretes substances into the blood or directly into an organ.
Differ from exocrine glands, endocrine glands have no ducts and secrete products (hormones) directly into blood.
Hormone - a substance produced by cells that helps specific groups of cells to perform specific functions. It is a product of endocrine gland which functions as chemical messengers to stimulate other cells.
Duct – a channel or tube that conveys a substance. It is part of the exocrine glands (such as salivary glands) which makes contact with surface .
The answer is sediments because sediments break down and are every where on earth also break down due to weathering
For questions 11-15
11. Magnesium Oxide is a combination between Magnesium and oxygen so the formula will be MgO
12. Calcium Chloride is a combination between Calcium and Chlorine, so the formula will be CaCl₂ the ₂ comes from the fact that there is two Chlorine atoms
13. Lithium Sulfide is a combination between Two lithium and a sulfur atoms,
so the formula will be Li₂S The ₂ coming from the two lithium atoms
14. Barium Selenide is a combination between Barium and Selenium so the formula will be BaSe
15. Aluminum Oxide is a combination between Aluminum and Oxygen, there are two Aluminum atoms and three Oxygen atoms, so it will make Al₂O₃
Hope this helps
