what substances play an important role in communication between cells in a multicellular organism by acting as a chemical message

The correct answer is - ligands such as hormones and neurotransmitters.

Explanation:

Communications between the cells of the unicellular organisms take place by the chemical signaling and the substances that help in sending chemical signals between cells are called ligands.

A ligand is a chemical molecule that binds with a specific molecule or a specific signaling receptor, a protein in or on the target cell. Hormones and neurotransmitters are the ligands that help in cell signaling and send chemical messages to the target sites.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

i think its 100.

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