Natural selection is the process that result in the adaptation of an organism to environment by means of selectively reproducing changes in its genotype, or genetic constitution. It is the a key mechanism of evolution. Charles Darwin popularised the term "natural selection" contrasting it with artificial selection, which is intentional, whereas natural selection is not.
To make it simple, let's have a group of beetle composing of green and some are brown as an example. here, there is a variation in traits. Since the environment could not support continuous population growth, not all species can reproduce to their full potential. Green beetles can easily be eaten by other species like birds compared to brown beetles. The surviving brown beetles will then generate brown offsprings because their trait has a genetic basis. Since more brown beetles survive and becomes more common in the population, the process continues until all individuals will eventually be brown. so basically, if you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome.
Technically speaking, an intrusion is any formation of intrusive igneous rock; rock formed from magma that cools and solidifies within the crust of the planet. In contrast, an extrusion consists of extrusive rock; rock formed above the surface of the crust.
hope this helps bye~glori
"Water quality" may include the amounts of dissolved oxygen
and the levels of algal growth, pollutants which may be present and the pH level. Water quality effects also which types of organisms can
survive in a body of water.
Shellfish require a high level
of dissolved oxygen and their abundance is an indication of good water quality. Shellfish are sensitive to changes in the ecosystem and they cannot easily escape changes in the water quality. These are one of the reasons why shellfish are good indicators of water quality.
Let’s say John’s age is x. Jim’s age is y. And Dana’s age is z. Then the equation would be:
1.) x + y + z = 167.
We also know that John (x) is 3 years older that Jim (y), so we can make the equation:
2.) y + 3 = x
We know that Jim (y) is 4 years younger than half of Dana’s age (z), so we can make this equation:
3.) z/2 - 4 = y
Now we can combine these equations so that we only have one variable remaining.
The second and third equation can combine to create:
4.) (z/2 - 4) + 3 = x
Then combine the first, third, and fourth equations to have only z as a variable.
5.) ((z/2 - 4) + 3) + (z/2 - 4) + z = 167
Simplify the fifth equation by isolating the variable:
z = 86
Dana’s age is 86. Now plug this into the remaining equations.
86/2 - 4 = 39
Jim is 39. Plug this number into the second equation.
39 + 3 = 42.
John is 42.
FINAL ANSWER:
John = 42
Jim = 39
Dana = 86
