B. a scanning electron microscope provides much better resolution than a compound light microscope.
Reasoning: The resolution of an electronic microscope is about 0,050 nm, whereas the resolution of a light microscope is about 200 nm.
10^{-8} mutations per nucleotide. If there are 100 million nucleotides per haploid genome, there are 200 million nucletides per diploid genome. Six mutations divided by 200 million is 10^{-8}.
Stomata are normally opened during the day because photosynthesis happens during the day. The stoma allow oxygen and carbon dioxide to diffuse through them.
Answer:
Primary lymphoid organs: the bone marrow and the thymus
secondary lymphoid organs: adenoids tonsils spleen
