A10-year-old male is stung by a bee while playing in the yard. he experiences a severe allergic reaction and has to go to the er. this reaction is the result of:

Anaphylaxis (commonly known as anaphylactic shock)

Explanation:

Anaphylaxis is a severe, life-threatening allergic reaction.

It is generally a result of the body's immune system overreacting to an allergen (such as a bee sting) by producing an overabundance of inflammatory mediators and cytokines from mast cells and basophils.

Normally, the mast cells and basophils produce an appropriate amount of inflammatory mediators and cytokines but for reasons that are not quite clear to science some people over produce these normal immune system response chemicals.  

This overreaction on the part of the body causes rapid inflammation of various tissues in the body including those of the upper respiratory system, which in turn can inadvertently shut down the ability of a person to breath. Anaphylaxis, therefore, is a very serious medical condition and proper precautions (antihistamine and or steroid shots like the EpiPen ) must be taken for those that suffer from this condition.

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation

i think its the first one