Here is a list showing how the bacteria grows:
Begin - 15
1st hour - 30
2nd hour - 60
3rd hour - 120
4th hour - 240
5th hour - 480
6th hour - 960
7th hour - 1,920
8th hour - 3,840
9th hour - 7,680
10th hour - 15,360
11th hour - 30,720
12th hour - 61,440
As you can see, the number of bacteria present is doubled at the end of each hour, as the question states. However, the question is not asking for the total number of bacteria at the end of the 12th hour; it is asking for the bacteria GROWN during the 12th hour.
Because there were 30,720 bacteria at the end of the 11th hour, and 61,440 at the end of the 12th, the number of bacteria that grew during that last hour must be 61,440 - 30,720 = 30,720 bacteria.
(P.S. the answer would be 61,440 if it was asking for the TOTAL number of bacteria at the end of the 12th hour)
Carbon dioxide (chemical formula CO2) is a colorless and odorless gas that is vital to life on Earth. This naturally occurring chemical compound is made up of a carbon atom contently double bonded to two oxygen atoms. Carbon dioxide exists in Earth's atmosphere as a trace gas at a concentration of about 0.04 percent (400 ppm) by volume.Natural sources include volcanoes, hot springs and geysers, and it is freed from carbonate rocks by dissolution in water and acids. Because carbon dioxide is soluble in water, it occurs naturally in groundwater, rivers and lakes, in ice caps and glaciers and also in seawater. It is present in deposits of petroleum and natural gas.
spent a few minutes on this
Mitosis (also known as cellular division) is just copying of cells. So the answer would be 18.If the question were about meiosis (sexual division), then the answer would be 9, because that would make 4 daughter cells, each encompassing half the original number of chromosomes (18).
Answer:
Control group: volunteer stationary bike riders in a pollution-free chamber
Experimental group: volunteer stationary bike riders in a chamber filled with air pollutants common to Los Angeles
Independent variable: exposure to air pollution
Dependent variable: The heart rates (physical fitness) of the volunteer riders.
Explanation:
In a scientific experiment, data is compared between the control group and experimental group to ascertain the effect of the independent variable on the dependent variable. A control group is the group in an experiment that is not treated with the independent variable i.e. the independent variable is controlled while the experimental group is the group that is treated with an independent variable.
N.B: The independent variable is the variable controlled by the experimenter in order to influence the dependent variable (measurable outcome).
In this experiment, the independent variable is the AIR POLLUTION the volunteer riders are exposed to while the dependent variable is the PHYSICAL FITNESS/ HEART RATES of the volunteer riders, which is dependent on the exposure to air pollution (independent variable).
The control group in this experiment is the volunteer riders placed in a POLLUTION-FREE CHAMBER where the independent variable cannot influence or have any effect on the measurable variable (dependent). The experimental group is the volunteer riders placed in a CHAMBER FILLED WITH AIR POLLUTANTS. The independent variable (air pollution) has been changed in the experimental group.
Answer:
Some animals have camouflage which helps them not get eaten.
Explanation:
