Question

For the following experiments, identify the IV (independent variable), DV (dependent
variable), EG (experimental group/s), CG (control group), CV (constants/controlled
variable(s), and the No. of Levels then specify the levels.

1. Three redwood trees are kept at different humidity levels inside a greenhouse for
12 weeks. One tree is left outside in normal conditions. The heights of the trees
are measured once a week.

2. Pea plant clones are given different amounts of water for three-week period. The
first pea plant receives 400 milliliters a day. The second pea plant receives 200
milliliters a day. The third pea plant receives 100 milliliters a day. The fourth pea
plant does not receive any extra water; the plant only receives natural ways of
receiving water. The heights of the pea plants are recorded daily.

3. One tank of gold fish is fed the normal amount of food once a day. A second tank
is fed twice a day. A third tank is fed four times a day during a six week study.
The fish’s weight is recorded daily.

Example:
You apply three sunflower plants with salt water. Each plant receives a different concentration of
salt solutions. A fourth plant receives pure water. After a two-week period, the height is measured.
IV: Concentration of salt solution DV: Height of the sunflower plant
EG: Plants receiving different concentrations of salt solution
CG: Plant receiving pure water
CV: same variety of sunflower, same amount of treatment, same observation period (2 weeks)
No. of Levels & Specify : 4 levels; 3 different concentrations of salt solutions and pure water

Answer 1

Answer:

INVENTION OF PRINTING PRESS÷

The printing press enabled the production of multiple copies of a manuscript and their spread all over Western Europe. In less than fifty years after the invention of Gutenberg printing press, about six million books had been printed. The invention of printing press not only spread knowledge widely, but also promoted critical thinking.

Explanation:

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