♥ They make use of a control group because its something that they can look into, something to compare to. <span />
Answer:
Option (2)
Explanation:
Strato-volcanoes are the steep, conical shaped, formed by the alternative beds of ash and lava. The magma in this type of volcano contains high silica content and are comprised of bubbles. When the gases are released from these bubbles, then a greater force is exerted from the bottom towards the surface. Due to this, they are very explosive and ejects a huge amount of materials during eruption. For example, Mount St. Helens
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Cinder cones are the simplest volcanoes with steep sides. They are made of the materials and semi solidified lava that are ejected from the vents of the volcano. Eruptions are often explosive due to the force exerted by the gas and the molten lava and are accumulated near the vent. For example, Paricutin.
<u>These two types of volcanoes are similar in terms of its eruption that is violent and explosive in nature. In addition to that, they both have steep sides.
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Hence, the correct answer is option (2).
<span>The four biological macromolecules are carbohydrates, lipids, proteins and nucleic acid. These macromolecules are known as polymers and are built when monomers join together by a process known as the dehydration reaction. The dehydration reaction is a chemical reaction that produces water (H2O) and the result is the covalent bonding of the two monomer molecules. The monomer molecules consist of nutrients found in the soil, as in the case of plants, and the intake of food as in the case of animals.
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I am pretty sure it is CD4 cell