What of these processes is a chemical change, not a physical change? 1. the burning of a match 2. the boiling of mercury 3. the dissolving of salt in water 4. melting ice 5. the breaking of a pencil?

A chemical change is one where the compounds are modified: a compound decomposes into its elements, or combine with other elements to form a different compound.

That is what happens when a match burns: oxygen reacts with the match compounds and form CO2(g), H2O(g) and other compounds depending on the composition of the match.

The other processes only involve a physical change of the compounds, but they remain being the same compounds (same elements with the same bonds).

Answser: option 1. the burning of a match.

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later