The answer is b, chromatin
blood rich in oxygen enters the lungs through the pulmonary artery in where the alveoli within the lungs exchange carbon dioxide and oxygen so the carbon dioxide leaves your body.
Hope this helps a bit
Hormones
The endocrine system includes various glands in the body that are responsible for secreting hormones into the bloodstream. Hormones are chemical substances produced by the body that regulate certain functions of cells and organs. Hormones can regulate sleep, sex, growth, stress, huger, metabolism, etc.
If your findings disproves your hypothesis then your hypothesis is probably wrong.
Scanning electron microscope- this is a type of microscope that uses beams of electrons to view the surface of a specimen. it is used to provide a three-dimensional image of cells
transmission electron microscope- uses beams of electrons to examine the insides of thin slices of materials. it is used to provide a two-dimensional image of cell structures
