Is xylem a internal and external adaptation? and ispholem an internal or external adaptation

In the context of the neural impulse, which of the following is true about the depolarization of neuron membranes?

Im inn a ! what"s the answer which of the following is one way creativity can scientists? by ensuring they follow the scientific method by increasing the amount of time it takes to complete scientific experiments by making sure they only try things that have already been proven by leading them to ask more questions about the natural world

Give an example of a trait that is controlled by more than one gene.