Question

gene expression is determined by several factors, including (1 point)
senescence
protein synthesis
chemicals in the body
the brain

Explanation:

Senescence is cell aging, not a direct gene expression regulator. Protein synthesis is the result of gene expression, not a determining factor. The brain does not directly control most gene expression across the body. Chemicals in the body (like hormones, transcription factors) directly modulate how genes are expressed.

Answer:

chemicals in the body