The base pairing rules in any DNA molecule are these:
• Adenine always pairs with Thymine(A-T)
• Cytosine always pairs with Guanine (C-G)
Streams that flow beneath melting glaciers leave long ridges of layered sediments, known as Esker. Eskers are formed within ice-walled tunnels by streams which flowed within and under glaciers. They tended to form around the time of the glacial maximum when the glacier was slow and sluggish and after the retaining ice walls melted away, stream deposits remained as long winding ridges.
-Plant cells are more rigid due to the cell wall.
Mendeleev organized the chemical elements based on their properties.
Mendeleev put elements in order in the periodic table according to their physical and chemical properties. He noticed that properties of elements were related to their atomic mass in a 'periodic' way, so he groups of elements with similar properties into vertical columns in the table. His periodic table had initial 63 elements which then expanded to 108 or 109 elements.
Answer: pressure changes
Valves of the heart open and close due to pressure changes
Explanation:
The veins are the blood vessels possessing valves. And because they carry blood away from the heart, the valves helps to prevent back flow of blood due to the low pressure of blood found in the veins.
Thus, Valves of the heart open and close due to pressure changes
