Answer:
Scientists use models to help them understand and explain ideas. Models explain objects or systems in a more simple way. Models often only show only a part of a system. The real situation is more complicated. Models help scientists to make predictions about complex systems. Some models are something that you can see or touch. Other types of models use an idea or numbers. Each type is useful in certain ways.
Explanation:
Physical Models
A physical model is a representation of something using objects. It can be three-dimensional, like a globe. It can also be a two-dimensional drawing or diagram. Models are usually smaller and simpler than the real object. They most likely leave out some parts, but contain the important parts. In a good model the parts are made or drawn to scale. Physical models allow us to see, feel and move their parts. This allows us to better understand the real system.
I would say the answer is c.
Answer:
C. plagioclase
Explanation:
From the magma silicate crystals are formed successively when the magma temperature reaches the typical melting temperature for each type of crystal. The first crystals formed at high temperatures can then change their composition or dissolve again. In this way the crystals already formed contribute their ions, molecules and atoms to magma and combine again forming new crystals whose melting temperature is lower than that of the first crystals formed. The new crystals are said to be stable at the lowest temperatures set now. These processes of change are called reactions. As several successive reactions occur as the magma temperature decreases the ordered series of reactions is called the BOWEN series in honor of the Canadian scientist who formulated this concept. There are two types of reactions, the continuous reaction and the discontinuous reaction.
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By continuous reaction a crystal formed at high temperatures such as a plagioclase rich in the Ca2 +</u> component gradually varies its composition by replacing a portion of the Ca2 + ions with the Na + ions and a portion of the Al3 + ions with the Si4 + ions. To maintain its neutrality, the replacement of Ca2 + by Na + is coupled with the replacement of Al3 + by Si4 +. The series of continuous reaction starts from the plagioclase rich in Ca2 +, passes through several plagioclase of intermediate composition towards the plagioclase rich in Na +