21. on first attachment is secondary succession
22. is the degree of variation of life....
genetic, species or ecosystem within a specific area, system or planet
23. the last one is wrong = )
C is the only bad sounding thing out of this bunch.
17, due to the gravitational forces and wind drag placed upon the arrow while it is in motion it will decrease the speed over a certain distance. Thus, resulting in the arrow to drop a little lower in height, hitting the bullseye.
Coin flipping simulates the events of mitosis and the production of sperm. This is because females carry XX chromosomes so all eggs will have a singular X chromosome. It is the sperm that determines the sex of the foetus: males have XY chromosomes and therefore sperm will carry either X or Y chromosomes (a 50/50 chance, just like flipping a coin)
The answer for this question would be choice <span>B) Water, rock, and surface materials, or the second option.</span>
