Question

growers have investigated storing pears under different conditions. the graph shows the results of one investigation.
effect of varying oxygen concentrations
on respiration rate of pears at
three different temperatures
source: journal of experimental botany.
select the correct answer from each drop - down menu to complete the sentences related to cellular respiration in pears.
for long - term storage of pears, the oxygen concentration should be
and the temperature should be
. this will result in the
amount of energy being used by the pears.

Explanation:

Step1: Analyze Respiration and Storage

For long - term storage, we want to minimize respiration rate (since respiration consumes energy and degrades the pears). From the graph, lower temperature and appropriate oxygen concentration (usually low, but let's check the trends). The curves show that at lower temperatures (7°C) and lower oxygen concentrations? Wait, no, the x - axis is oxygen concentration (%), y - axis is respiration rate. Wait, the three curves are for 7°C (yellow), 15°C (blue), 23°C (red). As oxygen concentration increases, respiration rate decreases? Wait, no, the curves are decreasing as oxygen concentration increases? Wait, no, the x - axis is oxygen concentration, and the y - axis is respiration rate. Wait, actually, for cellular respiration, at very low oxygen, anaerobic respiration occurs, but as oxygen increases, aerobic respiration can occur, but the graph here: let's see the trends. The 7°C curve (yellow) is the steepest, meaning at a given oxygen concentration, 7°C has lower respiration rate than 15°C and 23°C. And for oxygen concentration, to minimize respiration, we need to see: at lower oxygen concentrations? Wait, no, the curves start at (0,0) and decrease? Wait, no, the y - axis is respiration rate, x - axis is oxygen concentration. Wait, maybe it's a typo, and the x - axis is time? No, the label is oxygen concentration (%). Wait, maybe the graph is showing that as oxygen concentration increases, respiration rate decreases? That might be because at high oxygen, maybe some feedback inhibition, but more likely, the graph is showing that for long - term storage, we want low respiration. So lower temperature (7°C) and lower oxygen concentration? Wait, but the curves: the yellow curve (7°C) reaches a lower respiration rate at lower oxygen concentrations? Wait, no, let's think about the goal: minimize respiration. So lower temperature (since 7°C is lower than 15 and 23) and lower oxygen concentration? Wait, but the x - axis is oxygen concentration. Wait, maybe the graph is inverted. Wait, no, the key is that for long - term storage, we need to minimize the amount of energy used (respiration rate). So we need low respiration rate. From the graph, the lowest temperature (7°C) and the lowest oxygen concentration? Wait, no, the curves: at a given oxygen concentration, the 7°C curve (yellow) has the lowest respiration rate, 15°C (blue) middle, 23°C (red) highest. And as oxygen concentration increases, respiration rate decreases (since the curves are decreasing). Wait, so to minimize respiration, we need low temperature (7°C) and high oxygen concentration? No, that doesn't make sense. Wait, maybe the x - axis is time, and y - axis is respiration rate, and oxygen concentration is the variable. No, the label is oxygen concentration (%). Wait, maybe it's a graph of respiration rate vs oxygen concentration at different temperatures. The correct approach for long - term storage of fruits (like pears) is to have low temperature (to reduce metabolic rate) and controlled atmosphere (usually low oxygen, but maybe the graph is different). Wait, looking at the curves: the yellow curve (7°C) is the leftmost, meaning at a lower oxygen concentration, it has a lower respiration rate? No, the x - axis is oxygen concentration, so higher x is higher oxygen. The yellow curve (7°C) is the steepest, so at a given oxygen concentration, 7°C has lower respiration rate. And to minimize respiration, we need the lowest possible respiration rate. So the oxygen concentration should be such that we get the lowest respiration, and temperature as low as possible. So for oxygen concentration, looking at the curves, at lower oxygen concentrations (left side of the graph), but the curves start at (0,0). Wait, maybe the graph is showing that as oxygen concentration increases, respiration rate decreases (which is counter - intuitive, but maybe due to the experimental setup). So to minimize respiration, we need low temperature (7°C) and lower oxygen concentration? No, this is confusing. Wait, the question is: "For long - term storage of pears, the oxygen concentration should be [low/high] and the temperature should be [low/high] to minimize energy use (respiration)". From the graph, the 7°C (lowest temperature) curve has the lowest respiration rate at any given oxygen concentration. And as oxygen concentration increases, respiration rate decreases (from the graph's curve shape). Wait, but in reality, for fruits, controlled atmosphere storage uses low oxygen and low temperature. But according to the graph, if the curve is decreasing with oxygen concentration, then higher oxygen concentration gives lower respiration. But that might be the case here. So the oxygen concentration should be high (to get lower respiration) and temperature should be low (7°C) to get lower respiration. Wait, no, the curves: at oxygen concentration of 0, respiration rate is 0 (anaerobic), but as oxygen increases, maybe aerobic respiration starts, but the graph shows that as oxygen increases, respiration rate decreases. That might be because at high oxygen, some other process occurs, or the graph is mislabeled. But based on the graph, the lowest temperature (7°C) and the highest oxygen concentration (since the curve for 7°C is the leftmost, but as oxygen increases, respiration decreases). Wait, no, the x - axis is oxygen concentration, so higher x is higher oxygen. The yellow curve (7°C) is the leftmost, meaning at a given oxygen concentration, 7°C has lower respiration. So to minimize respiration, we need low temperature (7°C) and high oxygen concentration (since as oxygen increases, respiration decreases). But in reality, it's the opposite, but we have to go by the graph.

Step2: Determine Optimal Conditions

So for long - term storage, to minimize energy use (respiration rate), we need the lowest respiration rate. From the graph:
- Temperature: 7°C (lowest temperature among 7, 15, 23) has the lowest respiration rate at any oxygen concentration.
- Oxygen concentration: As oxygen concentration increases, respiration rate decreases (from the curve shape). So we need high oxygen concentration (to get lower respiration rate) and low temperature (7°C).

Wait, but this is conflicting with real - world knowledge, but we have to follow the graph. So the oxygen concentration should be high (or the lowest possible? No, the graph shows that as oxygen increases, respiration decreases). So the correct choices are: oxygen concentration should be high (or the value from the graph, but since it's a drop - down, probably "low" or "high". Wait, maybe the graph is actually showing that at lower oxygen concentrations, respiration rate is lower? Maybe I misread the axes. Let's re - examine: the y - axis is respiration rate, x - axis is oxygen concentration (%). The three curves: yellow (7°C), blue (15°C), red (23°C). At x = 0 (oxygen concentration 0), all curves start at 0. As x (oxygen concentration) increases, the curves decrease, meaning respiration rate decreases as oxygen concentration increases. So to minimize respiration rate, we need high oxygen concentration (high x) and low temperature (7°C, since yellow curve is lowest at any x).

So the oxygen concentration should be high (or the maximum possible, but in the drop - down, probably "low" or "high". Wait, maybe the graph is inverted. Alternatively, maybe the x - axis is time, and y - axis is respiration rate, with oxygen concentration as the curve parameter. No, the label is oxygen concentration (%).

Assuming the graph is correct, for long - term storage, we want low respiration rate. So:
- Oxygen concentration: high (since as oxygen increases, respiration decreases)
- Temperature: low (7°C, since lower temperature gives lower respiration at any oxygen concentration)

Answer:

Oxygen concentration: high (or the appropriate option from the drop - down, e.g., if options are low/high, then high); Temperature: low (e.g., 7°C, or the option for low temperature from the drop - down). The final answer for the conditions: oxygen concentration should be high and temperature should be low (7°C) to minimize energy use (respiration rate).