Carbohydrate macromolecules, or Polysaccharides
Heyo, first off the dependent variable is the variable you measure at the end of the experiment, so basically the outcome of the experiment.
Sara and Juan used the four different types of soils which was considered as the independent variable. The independent variable is the variable you change at the beginning of the experiment.
The dependent variable of the experiment which was measured last was seed germination, and plant growth.
Answer:
A. If the aerobic pathway—cellular respiration—cannot meet the energy demand, then the anaerobic pathway—lactic acid fermentation—starts up, resulting in lactic acid buildup and "oxygen debt."
D. The rate of energy demand determines how the muscles will obtain energy, either from cellular respiration or from lactic acid fermentation if not enough oxygen is present.
Explanation:
It is important to consider that Kenny hikes all day but at a steady pace, whereas Janelle runs very fast. So Kenny's case, the supply of oxygen is sufficient to maintain aerobic respiration within the muscle cells. During this process only CO2, Water, and ATP are produced; therefore, there is no oxygen debt. We should keep in mind that the body shifts to anaerobic metabolism only when the supply of oxygen is limited.
In Janelle's case, running fast would need energy at higher rates and the supply of oxygen would not be sufficient to generate a high amount of ATPs. Therefore, to compensate for this deficiency, cells will start fermenting glucose to lactic acid and produce ATP and maintain energy demands. This lactic acid causes fatigue and this is why Janelle has aching and breathing hard. Breathing hard is also automatic reflux to inhale more oxygen and meet oxygen demands but even breathing hard would not be able to make it and the body will shift to anaerobic respiration automatically.
This question is incomplete as the specific food chain is not provided. In general, a food chain will have a primary producer at the base of the chain. This is an organism that is able to utilise a form of energy to convert carbon dioxide in the atmosphere to a carbohydrate. For terrestrial food chains, these are typically plants, who by utilising the energy from the sun, are able to convert carbon dioxide to carbohydrates. The subsequent level in the food chain may be a primary consumer, typically herbivores, that consume plant matter. Subsequent links in the chain would typically be secondary consumers, who would be carnivores, omnivores or decomposers. Carnivores would typically be predators and would be at the apex of the food chain. Energy is lost from one link to the subsequent link in the food chain, through basic respiration and inefficient energy transfer from one link to another. This explains why more resources (land, water and air) are required to grow meat rather than plant matter. More of the sun's energy is available within the lower trophic levels in a food chain, before much of it is lost as energy moves up the food chain. An easy example to illustrate this is that much of the livestock raised in the USA is fed grain. If people rather ate the grain than the livestock, they could obtain all their required energy from a smaller amount of grain then would be needed to raise the meat they require.
