Final answer:
True, signaling molecules are both amplified and integrated by various factors in multicellular organisms. This complexity allows a small number of signaling molecules to generate a significant cellular response and enables the integration of multiple signals for precise cellular responses.
Step-by-step explanation:
The statement that signaling molecules are amplified and integrated by multiple factors is true. In biological systems, specially in multicellular organisms, signaling is a sophisticated process involving signal transduction, which allows a few signaling molecules interacting with cell surface receptors to amplify a response through a cascade of enzymatic reactions. This signal amplification leads to a magnified effect, which enables the cell to produce a large response from a seemingly minute interaction.
Moreover, the complexity of signaling mechanisms in multicellular organisms arises from the need to coordinate and integrate multiple signals. Cells often have a variety of receptors to respond to different stimuli, and signal integration occurs when signals from two or more different cell-surface receptors come together to activate a common response. This ensures that a cell commits to a specific action only when multiple external requirements are met. Signaling in multicellular organisms is indeed more complicated than in single-celled organisms because of this multiplicity of signals and responses, as well as the variations in protein expression among different cell types.