Which of the following do scientists think is responsible for climate change?
a. nitrogen
b. smog
c. acid rain
d. carbon dioxide

Describe the primary and secondary immune response in terms of speed and number of antibodies produced?

Adrought killed all the plants in an agricultural farmland. gradually, due to wind and some birds for. nearby areas, new plants started sprouting l. what stage of succession was taking place in the farmland? a) competition b) nudation c) ecesis d) reaction e) migration

Why are common names a problem for scientist?