Answer:
Underground stem, Aerial stem, and subaerial stem.
Explanation:
Plant stems can be Underground stem, Aerial stem, and subaerial stem due to its presence and strength of the stem. Underground stem are thick stems that run below the ground surface. e.g rhizome. Aerial stems are thin stems that can not stand erect. Examples include watermelon and strawberry etc. Subaerial stems are very thin stems that do not rise up but grow just above the ground. for example, water plantain, flowering rush etc.
Excitatory neurotransmitters cause the neuron to fire, and Inhibitory neurotransmitters cause the neuron not to fire.
Impulses are the signals passed from one neuron to another on the action of a stimulus. The impulses passed can be electrical or chemical. Neurotransmitters are the chemical molecules that help in the transfer of impulses between two neurons.
Chemicals like epinephrine, norepinephrine, and glutamate when released from the synaptic cleft of one neuron activate the receptors of other neurons, thereby initiating the other neuron to fire. These chemicals are called excitatory neurotransmitters.
Chemicals like GABA and glycine, when released from the synaptic cleft of one neuron do not activate the receptors of other neurons and hence the neurons will not fire the impulse. These chemicals are called inhibitory neurotransmitters.
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As Earth rotates, different parts of Earth receive sunlight or darkness, giving us day and night. Since different parts of Earth enter and exit daylight at different times, we need different time zones. In the late 1800s, a group of scientists figured out a way to divide the world into different time zones.
By the late 1830s, botanist Matthias Schleiden and zoologist Theodor Schwann were studying tissues and proposed the unified cell theory. The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
