Use the information below to answer the question following this description: Maggie read that some plants grow better if the soil is acidic.

#1: She wonders of a plant can really grow when it is exposed to acid.

#2: Maggie thinks that plants she will not grow better when acid is added to the soil.

#3: She puts potting soil in two planting containers and transplants two of her geraniums that seem about the same size into the pots. She puts the pots in the same location so that both get the same sunlight each are at the same temperature and she makes sure they get the same amount of water.

#4: However, Maggie puts a tablespoon of acidic vinegar in the water she gives to one of the plants.

#5: She measures the growth every week for five weeks.

#6: Maggie finds that the plants in the acidic soil had a greater height than those without acid.

QUESTION: Which statement number is describing the independent variable?

a. 3
b. 4
c. 5

On a backpacking trip, kenny hikes all day at a steady pace, covering 30 kilometers and burning 4000 calories. at the school track, janelle runs the 100-meter sprint in 13.5 seconds, burning 10 calories. afterward, janelle’s leg muscles are aching and she is breathing hard, while kenny maintains normal breathing all day, even though he burns 400 times more calories than janelle. which two statements offer the best explanation for this phenomenon? 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." b. aerobic cellular respiration produces more energy, but its use is limited because of lactic acid buildup in the muscles and the resulting "oxygen debt." c. after about 90 seconds of intense exercise, the muscles become depleted of oxygen, and anaerobic respiration can no longer function to produce atp, resulting in "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.