84. using a specific chemical, a cell biologist has blocked one type of channel-linked receptor in a lab rat's liver tissue. what was the likely mechanism of the chemical she used?

The chemical inhibits the binding of ligand with receptor.

Explanation:

Channel linked receptor are activated by the binding of the ligand with the receptor. Ligand gated ion channel are also known as the channel linked receptors.  

The chemical used by the cell biologist has blocked one of the channel-linked receptor in a lab rat's liver tissue. The chemical must inhibits the receptor binding with its ligand.

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .