The histamine h1 receptor is one of several existing histamine g protein-coupled receptors. depending on many factors, including the type of receptor, histamine can trigger a variety of responses, including vasodilation, smooth muscle contraction, stimulation of gastric secretion, cardiac stimulation, and increased vascular permeability (causing runny nose and watery eyes). which of the following could account for the different cellular responses to histamine? select all that apply.
view available hint(s) o
a) the types of relay molecules within the cell
b) the enzyme that is activated by the g protein associated with the receptor o
c) the type of second messengers involved in the signal transduction pathway
d) the cell type in which the histamine receptor is located the type of signaling molecule

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.