histamine is a chemical substance released in inflammatory and allergic responses. the histamine h1 receptor is a g protein-coupled receptor that activates phospholipase c in response to the binding of histamine. complete the flowchart showing the process of histamine signal transduction from the h1 receptor.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.