Answer:
Oxygen and pyruvate.
Explanation:
The krebs cycle is a stage of cellular respiration and occurs in aerobic organisms. In this case, we can say that the Krebs Cycle only occurs in the presence of oxygen, being essential for the completion of cell respiration.
The Krebs cycle only occurs after the completion of glycolysis, as it needs to be initiated by pyruvate, which is a molecule resulting from glycolysis. In this case, in addition to oxygen, the presence of pyruvate is essential for the krebs cycle to occur.
The answer is b. <span>A decrease in plant life would cause carbon dioxide levels to increase and oxygen levels to decrease.
</span>In the photosynthesis, plants take carbon dioxide and water
and convert it into glucose and oxygen using the energy of sunlight. A decrease of plant life in the biosphere will increase a level of carbon dioxide in the atmosphere. Fewer plants mean fewer photosynthesis processes, and, thus, decreased levels of oxygen in the atmosphere.
Scientists classify stars by size, brightness, and temperature. The correct answer will be D.
Hypothesis: If plants are placed in white light, then the will grow better than plants in other colours of light.
Independent variable: Colour of light.
Dependent variable: plant growth.
Control group: the plant in the closet.
Experimental group: the plant is the other light colours.
Constants: miracle grow and amount of water.
Measurements: height of plants.
