The substance is guided through a protein embedded in the membrane from high to low concentration since this not considered as active.
Stimulus stimulate the sodium ion voltage gated channel to open in the axon. This allow many Na ion to enter the axon and causes depolarisation as the pd in the axon getting less negative charge (from -70mV to -50mV).
The correct answer is the second option. Animals have two major types: vertebrates and invertebrates. Vertebrates are animals that have backbone while the invertebrates do not have one. Examples for vertebrates are birds and mammals while the latter are insects and squid.
Shawna's work on her blog about cars would be best described as
unreliable. Although speaking outside of a scientific context, she is
very knowledgable about cars, it is also important to consider that all
of her information comes either from second-hand sources, or from
opinions that she personally holds, which is not the basis for reliable
information.
When particles spread out it is called diffusion.
