The appearance of fossils would the the answer.
Although there has been some scientific debate about what fossil strata should mark the beginning of this period, the "International Geological Congress" determined that the Cambrian period was approximately 543 million years ago of which the first appearance in the fossil record of worms that made horizontal burrows was discovered.
Neurotransmitters are the chemical molecules, which help in transfer of the signals from one neuron to another. Inside the neurons, the signals are transferred as electrical signals, but at junction of two neuron, which is known as synapse, the signals are transferred in chemical forms.
These neurotransmitters have a definite shape and are recognized by the receptors present in the receptor site of the succeeding neuron. The neurotransmitters from the synapse binds to the receptor site of the receiving neuron. binding of the neurotransmitter to the receptor causes excitation of the receiving neuron, which also known as postsynaptic neuron.
Hence, Like a key in a lock, the shape of the neurotransmitter must bind with the receptors of the receiving neuron.
Answer:
The physical stimulus is the only part of the test that is measureable, and therefore, knowable. The stimulus is our anchor for our estimate of the listener's perception.
it gives off protons because it's in a basic solution (pH>7)
The concentration of lipids necessary to prepare liposomes with a diameter of 250 nm is 0.30 mM.
<h3>What are liposomes?</h3>
Liposomes are vesicles which are made up of a lipid bilayer membrane.
Liposomes are important as delivery vehicles for substances such as drugs.
Ultrasonication is a method of liposomes preparation.
Solution of liposomes is dependent on the size.
The larger the diameter, the smaller the l elution volume. Also, increasing lipid concentration will decreases elution volume.
Therefore, the concentration of lipids necessary to prepare liposomes with a diameter of 250 nm is 0.30 mM.
Learn more about liposomes at: brainly.com/question/15852922
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