Final answer:
Option (c) 'the acorns of the black oak tree require two years of growth' is the correct line from the passage that supports the inference that black oak acorns take longer to develop.
Step-by-step explanation:
Oak trees are known for their slow growth and their acorns, which are their seeds. There are around 50 kinds of oak trees native to America, split almost evenly across the Rocky Mountains. The passage describes the characteristics that allow for the identification of various types of oak trees.
For instance, the white oak group is known for its light-colored bark, bearing a crop every year, and not retaining acorns through the winter. The black oak group, however, contains trees that have bark that is usually dark in color, spiny-tipped leaves, and most notably, the acorns of black oak trees require two years to develop. This extended development period is highlighted by the presence of half-grown acorns on the trees all winter, suggesting that the acorns take longer to reach maturity than some might expect.
When considering the inference that black oak acorns take longer to develop, option (c) 'the acorns of the black oak tree require two years of growth' directly supports this inference. This is because it states explicitly that the development cycle for black oak acorns spans two years, unlike the white oak acorns which are shed annually. This indicates a longer developmental period for the acorns of black oak trees. Therefore, the correct answer to the question is option (c).