Answer:Small hydrophobic molecules and gases like oxygen and carbon dioxide cross membranes rapidly. Small polar molecules, such as water and ethanol, can also pass through membranes, but they do so more slowly.Semipermeable membranes, also termed selectively permeable membranes or partially permeable membranes, allow certain molecules or ions to pass through by diffusion.
Explanation: hope that helps
Answer: molecule
Explanation: common knowledge
Nonrenewable resources are used commonly and are quickly running out, and it takes longer for us to form more of these.
A neurotransmitter can have an excitatory or inhibitory effect on the postsynaptic cell, depending on <u>which of its </u><u>receptor(s</u><u>) are present on the </u><u>postsynaptic</u><u> (target) cell.</u>
<h3>How do excitatory and inhibitory neurotransmitters act?</h3>
Sometimes neurotransmitters can bind to receptors and cause an electrical signal to be transmitted through the cell (excitatory). In other cases, the neurotransmitter can prevent the signal from continuing, preventing the message from being carried (inhibitory).
With this information, we can conclude that a neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse.
Learn more about neurotransmitter in brainly.com/question/9725469
#SPJ1
An air mass bringing dry, frigid winds to North Dakota
