Passage II

Heliconia metallica is a plant found in the understory of tropical rain forests. (The understory is the area below the forest canopy.) H. metallica flowers are normally pollinated by hummingbirds. The flowers can be self-pollinated (egg and pollen are from the same H. metallica plant) or cross-pollinated (egg and pollen are from different H. metallica plants). The following study was conducted to investigate the effects of different pollination treatments on fruit production and seed mass in a population of H. metallica.

Study

Before pollination could occur, the anthers (pollen-producing structures) were removed from each of 400 H. metallica flowers. Then, the flowers were covered with nylon bags to prevent the normal pollinators from pollinating the flowers. The covered flowers were divided equally into 4 groups (Groups 1-4), and each group received a different pollination treatment (see Table 1). Four weeks after the pollination treatments, the percent of flowers that produced fruit and the average mass per seed were determined for each group (see Figures 1 and 2, respectively).

Table and figures adapted from Matthias Schleuning et al., "Effects of Inbreeding, Outbreeding, and Supplemental Pollen on the Reproduction of a Hummingbird-pollinated Clonal Amazonian Herb." @2010 by The Author(s).

8. One of the questions about H. metallica plants that the study was designed to answer was which of the following?

Answer and Explanation

Your Answer is

Correct Answer is G

Explanation

Looking at table 1, Group 1 is self-pollinated, while Groups 2 & 3 are Cross-pollinated, so the pollination method is an independent variable;

Look at the dependent variables of figure 1 and figure 2 respectively It is the percent of flowers that produced fruit and average mass per seed;

So the experiment wants to study the influence of the independent variable pollination method on the two dependent variables