Answer: Light
Explanation: Light can travel in empty space or vacuum. It doesn't need any medium to which it travels.
There are advantages<span> to being </span>multicellular<span> rather than unicellular. These include allowing: The organism to be larger. Cell differentiation (having different types of cells with different functions)</span>
Answer:
A negative feedback initiated by the external simuli or the products of a reaction aims to reduce the products/ output of the reaction. Hence In negative feedback the stimulus is reduced. An example of a negative feedback would be if a person had an elevated body temperature, the homeostatic response would be to lower the body temperature.