Fluorine
Check out the periodic table. Exact mass number of Fluorine should appear as 18.99...
The answer is speciation by geographic isolation. When the population of a species gets separated due to reasons such as continental drift, mountains, canyons, etc. then each separated group of population may survive and adapt to their respective environment leading to speciation. These barriers do not allow the evolving populations to interbreed initially and over time when they evolve into different species they become completely reproductively isolated.
Answer:
- The recoil force of a bazooka (reaction) + the accelerating force of a missile
- When walking, the foot pushes down and back (action) + the floor pushes up and forward
- When a rocket is taking off, the combustion of the fuels (an action) creates a direct and opposite reaction which is the thrust of the rocket upwards.
Explanation:
Newton's third law states that for every action (force) in nature there is an equal and opposite reaction. Simply put, forces act in approximately equal and opposite pairs (Action and Reaction).
This law is one of the reasons why the foundation of a building must be built in such as way that is exerting equal and opposite pressure against the building which it is carrying. When the forces are equal, the balance of forces are said to be in equilibrium.
Cheers!
