請依下文回答第 46 題至第 50 題 These satellite images show the ebb and flow of plant life on earth over three years, taken by a NASA satellite
called SeaWiFS. The blue areas are void of plants, the red spots indicate an overabundance, and the green areas show
where plants are thriving. This is the earth breathing. The plants are taking up CO2, and they’re breathing out oxygen.
As suggested by oceanographers, almost half of that activity is going on underwater. The oceans are teeming with
tiny microscopic plants called phytoplankton. They are at the bottom of the food chain, and they basically feed all sea
life. Like all plants, phytoplankton absorbs CO2 from the atmosphere.
These images show that phytoplankton boomed over the last three years. That’s one of the key benefits of these
satellite images. Over time, scientists will use them to help predict how plants might respond as we burn more fossil
fuels, and as global CO2 levels rise. Many scientists think such greenhouse gasses will cause global warming. They
suggest that it is related to recent climate change. However, what they don’t know is how life in the ocean will respond
over the long haul if CO2 levels keep rising.
【題組】48 How does one know that the earth is breathing?
(A) Because satellite images show no change in the green areas.
(B) Because satellite images show that the plants’ breathing activities happen underwater.
(C) Because satellite images show that plants are absorbing CO2 and producing oxygen.
(D) Because satellite images show overuse of fossil fuels.