The three-dimensional compositions have more silicon in comparison to those composed of independent tetrahedra.
The silicate minerals refer to the most general of Earth's minerals and involve feldspar, quartz, mica, pyroxene, amphibole, and olivine. On the other hand, the silica tetrahedra composed of oxygen and silicon, produce sheets, chains, and frameworks, and bonds with other cations to produce silicate minerals.
Answer:
nucleus,chloroplast,cell wall, cell membrane
Explanation:
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:
There are two possible answers: Deep-sea vents provided the energy needed for the first organic compounds to form OR self-replicating RNA molecules passed on genetic information.
Explanation:
The reason for the first answer is due to the hypothesis that indicates that life (organic molecules) arose from inorganic molecules synthesized from the amino acids in those energy vents. This is called the metabolism first hypothesis. The Miller-Urey Experiment provided evidence that organisms could rise from inorganic molecules (they simulated under the conditions you would see on early Earth). The second hypothesis is the RNA World hypothesis (second answer) which suggests that the formation of RNA that could replicate (possible due to mutation or evolution), led to life that could preserve its genetic integrity through replication (greater stability to the organism) and create lipid bi-layer membranes/other organelles. Some scientists support the Metabolism First Hypothesis, while others are skeptical (this goes for the RNA World Hypothesis as well). However, the RNA World Hypothesis is for more reasonable in the fact that its main point is the fact that RNA molecules were able to replicate and maintain genetic stability despite early Earth conditions. Although either hypothesis could explain why all organisms share the same genetic code, the RNA World Hypothesis better explains the universality of DNA/RNA of genes that we see today.
the answer is the last one
