The reason why nost scientists thought that the first true cells formed on Earth were anaerobic is being shown in the second option :B. because there was no oxygen on early Earth. Paying attention to this fact scientists discovered that first cells were prokaryotes and greatest part of them created oxygen as a toxic by-product of their own metabolism which make them understand how the planet was provided with oxygen and made a conclusion that first cells were anaerobic.
Answer:
A.) Smell is a chemical sense.
B.) Odorant molecules dissolve in mucus before stimulating a receptor
C.) Olfactory receptors have hairs on the apical surface that respond to stimuli
Organisms that survive a new environment are said to have adapted to their surroundings.
