Question

1. Plants and animals play major roles in cycling materials in ecosystems. The diagram below represents one particular cycle. Letters W and Y represent different PROCESSES. Letters X and Z represent different GASSES. What reaction below represents the process going on at "W"?
A. 6CO2 + 6H2O → C6H12O6 + 6O2
B. C6H12O6 + 6O2 → 6CO2 + 6H2O
C. Ca + 2HCl –> CaCl2 + H2
D. CaCl2 + H2 –> Ca + 2HCl

2. Which of these relationships is the best example of competition? Use the food web to answer question 3.
A. Toad and rabbits
B. hawk and toad
C. grasshopper and plant
D. sparrow and toad

3. What is likely to happen if the grasshopper population decreases?
A. decrease in the producers and the secondary consumers
B. an increase in the producers and the secondary consumers
C. an increase in the producers and a decrease in the secondary consumers
D. an decrease in the producers and an increase in the secondary consumers

4. What does this enzyme temperature graph tell you about the environment in which this enzyme functions?
A. its optimum temperature is 20 degrees Celsius
B. its optimum temperature is 30 degrees Celsius
C. its optimum temperature is 35 degrees Celsius
D. its optimum temperature is 40 degrees Celsius

Answer 1

Answer 1:

The correct option is A. 6CO2 + 6H2O → C6H12O6 + 6O2

Explanation

The letter W depicts the mechanism of photosynthesis taking place. As a result of photosynthesis, glucose and oxygen will be made. The Oxygen will then be released and taken up by the animal during the process of respiration.

Answer 2:

The correct option is D.  

Explanation

The animals that show competition are sparrows and toad. As we can see from the diagram of the food web, sparrow and toad are main competitors in the food chain. Competition is a mechanism in food web in which two organisms compete for resources in a habitat. They usually have the same enemies and same food sources to feed on. As in the diagram, sparrow and toad have the same enemy i.e hawk and same food source i.e grasshopper.

Answer 3:

The correct option is C. An increase in the producers and a decrease in the secondary consumers

Explanation:

Grasshoppers are the primary consumers in the given food web. A decrease in the population of grasshoppers will lead to an increase in the population of the producers. This is because there will be less consumers to feed on the plants. Sparrow and toad are the secondary consumers according to the diagram. As they feed on the grasshoppers, a decline in the population of grasshoppers will also lead to a decline in the population of sparrow and toad. As they will have limited amount of food and will have to under go severe competition for food.

Answer 4:

The correct option is D. Its optimum temperature is 40 degrees Celsius.

Explanation:

Optimum temperature can be described as the temperature at which the activity of the enzyme is fastest. Different enzymes have different optimum temperatures. The graph in the figure shows that the activity of purified phosphatase enzyme was maximum at 40 degrees Celsius. Hence, this temperature is the optimum temperature for this enzyme.