In an experiment, acid was added to two solutions:

Solution 1: distilled water only

Solution 2: distilled water containing sodium bicarbonate

Then, the pH of each solution was taken.

Solution 1 had a final pH of 4.5, while Solution 2 had a final pH of 6.8.

Which of the following statements explains the difference between the two solutions?

Choose 1

(Choice A)

Sodium bicarbonate acted as a pH buffer in Solution 2.

(Choice B)

Hormones released in Solution 2 allowed it to maintain a higher pH.

(Choice C)

The water in Solution 1 had a lower starting pH than the water in Solution 2.

(Choice D)

Sodium bicarbonate increases the temperature of a solution, which helped raise the pH of Solution 2.

The empty trna moves off and picks up another matching amino acid from the cytoplasm in the cell. the anticodon of the trna, with its attached amino acid, pairs to the codon of the mrna, which is attached to a ribosome. this sequence is repeated until the ribosome reaches a stop codon on the mrna, which signals the end of protein synthesis. the ribosome forms a peptide bond between the amino acids, and an amino acid chain begins to form. when a second trna with its specific amino acid pairs to the next codon in sequence, the attached amino acid breaks from the first trna and is bonded to the amino acid of the second trna.

First dropdown options: a. runoff b. condensation c. evaporation second dropdown options: a. photosynthesis b. transpiration c. sweating third dropdown options: a. raindrops b. clouds c. animals

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.