19. What pattern do you see in the number of native birds?
a. The number of native birds increases from the interior to the edge of the forest.
b. The number of native birds increases from the edge to the interior of the forest.
c. The number of native birds shows no pattern.
d. No pattern can be detected because there were no birds towards the edge of the forest.
20. What pattern do you see in the plants along the transect from the edge to the interior?
a. The number of native plants increases while the number of non-native plants decreases.
b. The number of native plants remains the same while the number of non-native plants increases.
c. The number of native plants increases while the number of non-native plants remains the same.
d. The number of native plants and non-native plants both increase.
21. What might be causing the above patterns?
a. Both native plants and birds prefer lower temperatures.
b. Non-native plants prefer higher temperatures.
c. Both native plants and non-native plants prefer lower temperatures.
d. Native birds prefer non-native plants.
Answer the following questions in the space provided.
22. A population of birds is declining in size. List three factors that may explain this decline.