Compound microscope
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Further explanation</h3>
In 1665, Robert Hooke used a compound microscope to observe cells. Hooke observes the cell walls of dead plants (in the form of cork) when they appear under a microscope. He named it the cell because it looked similar to a cellula or small room inhabited by monks.
Development of microscopy:
- 1590: Hans and Zacharias Janssen, as Dutch lens grinders, mounted two lenses in a tube to produce the first compound microscope.
- 1660: Robert Hooke published <em>Micrographia</em>, containing detailed observations of biological materials made with the best compound microscope.
- 1676: Anton van Leeuwenhoek was the first person to observe a live cell under a microscope, i.e., the algae Spirogyra.
- 1931: Ernst Ruska constructed the first electron microscope. With the invention of the electron microscope, many infectious agents smaller than bacteria could be seen.
Until now, we can see how important the use of microscopes, especially in microbiology, that is the study of microorganisms.
<h3>Learn more</h3>
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- The theoretical density of platinum which has the FCC crystal structure. brainly.com/question/5048216
Keywords: compound microscope, Robert Hooke, cells first observed, cork, dead plant, walls, Anton van Leeuwenhoek
Answer:
Carbon dioxide, Oxygen
Explanation:
The circulatory system of our body works following two pathways -
In pulmonary pathway the deoxygenated blood is carried to the lungs while in the second pathway, known as systemic pathway, the oxygenated blood is carried to the various parts and organs of our body. Thus the completed sentence in the question will be -
Blood being pumped by the heart is circulated in two circuits. One circuit carries blood with high levels of carbon dioxide to the lungs, and the other circuit carries blood with high levels of oxygen to the body.
The correct option is D.
A scientific theory refers to an in depth explanation of a specific observed phenomenon while a scientific law refers to a statement about a particular observed phenomenon. Scientific laws are usually presented in form of mathematical expressions for the observed phenomenon; examples of these are Newton's law of gravity, Mendel's law of independent assortment, etc. Scientific law basically describes the observations that are made and these observations are usually similar to other related observations.
(1) A system can refer to a organs that work together for digestion.
(2)A system is a set of rules, an arrangement of things with a group of related things that work toward a common goal.