When something is burning is that physical or chemical change

There are specialized producers that live in warm water vents deep in the ocean. these producers do not per-form from photosynthesis, but instead perform a similar process with iron and other chemicals. why do you think these producers use this process instead of photosynthesis?

Lucia is walking barefoot in her yard. she accidentally steps on a nail. how will her nervous system work to generate a reaction? arrange the eventschronologically.

A(n) is a molecule influences the way that a molecule reacts.