Answer:

Explanation:
1. Molecules of P₄
The molecular formula of phosphorus is P₄.

2. Atoms of P
One molecule of phosphorus contains four P atoms.

Plants and animals RE a carbon source during respiration. they take in Oxygen and give out Carbon (IV) oxide as a by product. Combustion of fossil fuels is also source of carbon (IV) Oxide.
Formation of fossils from dead plants and animals is a carbon sink. photosynthesis is also a carbon sink as plants take in carbon (IV) Oxide that is used to make food.
Answer:
Growing population
The worlds developing regions will see 1.2 billion people added, a 20.7% increase; while the population of developed countries will increase a mere 3.3% adding 41 million to the current 1.3 billion people.
Answer:
C. Their properties change completely.
Explanation:
The electron configurations of the elements show a periodic variation with increasing atomic number. Consequently, there are also periodic variations in physical and chemical behavior.
When atoms interact to form a chemical bond, they combine in order to <u>achieve a more stable electron configuration.</u> As a consequence, the compounds formed exhibit completely different properties.
For example, when solid magnesium burns in air, it forms both magnesium oxide and magnesium nitride, which are gases.