Nhận biết (M1)

Visiting flowers that produce high volumes of nectar allows hummingbirds, including long-billed hermits, to maximize their foraging efficiency. But nectar can’t be seen from outside the flower, and while some studies have suggested that petal length may indicate nectar volume, María A. Maglianesi and team found no such association among hummingbird-visited plants at Los Cusingos Bird Sanctuary and other sites in Costa Rica. The researchers hypothesize that by driving hummingbirds to visit more plants in search of high-reward flowers, plants’ lack of reliable signaling may increase chances of pollination.

Which choice best describes the function of the underlined portion in the text as a whole?

• A.

  It acknowledges research findings, which weren’t replicated by the study discussed later in the text, positing a relationship between floral traits that potentially underlies hummingbird foraging decisions.

• B.

  It summarizes contradictory study findings concerning a floral trait that influences hummingbird foraging patterns, which the study mentioned later in the text aimed to resolve.

• C.

  It suggests that a hypothesis discussed later in the text regarding a potential visual cue that hummingbirds rely on to increase their foraging efficiency has little support from the broader scientific community.

• D.

  It attributes the inconclusive findings reported in the text regarding the influence of a particular floral trait on interactions between hummingbirds and plants to differences in study sites.