Charles Keeling’s work at the National Oceanic and Atmospheric Administration (NOAA) Mauna Loa Observatory paved the way to understanding how human activities can lead to global warming.
Which greenhouse gas did Charles Keeling measure at the observatory?
A)
carbon monoxide
B)
methane
C)
nitrous oxide
D)
carbon dioxide

Which organism is the producer in this food web? 7th grade question. a) arthropods b) birds c) fungi d) plants

In sexual reproducing animals once fertilization of the egg takes place, the exists as a single cell until cell division begins. a) egg b) larva c) sperm d) zygote

An ecologist studied the same species of deer during the summer and the winter. she noticed that during the summer, when there was plenty of food, the deer were energetic and playful. however, during winter when food was scarce, the deer moved more slowly and did not run unless they needed to escape a predator. which scientific fact is best supported by her observations?