This might have been the cause of not being exposed to this specific pollen during his years in Chicago. Allergic reactions can develop when the stimuli presented even when its not contagious causes the immune system to trigger and act in a defensive stance. This delayed effect may have been the cause of the sudden expression of the immune system.
Answer:
A
Explanation:
Photosynthesis produces carbon dioxide (chemical gas) which is used in cellular respiration to make oxygen. That oxygen is then used in photosynthesis to make more carbon dioxide and so on.
A hypothesis should be tested by changing one variable in an experiment.
They classify on how they reproduce.
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females.
