When designing a science presentation, look for credible sources. science doesn’t show bias, but humans do. avoid sites and articles that provide facts without citing proper scientific evidence. you must be able to identify reliable sites so that the data in your presentation is credible. use sources that end in .gov, such as cdc. gov. these government sites are reliable sources. you can also use sites ending in .edu. they are usually trustworthy, but sometimes students, not scientists, write content for .edu websites. always identify the source’s author before proceeding. some .org and .com sites are credible, but it’s important to verify their authenticity. when reviewing a source, ask these questions: who is the author? is this person an hiv or aids expert? what is the document’s purpose? does the document state facts that scientists can prove with evidence? are there opinions in the document? how old is the document? do other credible sources support the statements in the document? search for credible websites and note the information they contain. write down two sources that you will use for your presentation, and cite them using modern language association (mla) citation methods.

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blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.

answer and explanation;

volcanic rocks are igneous rocks which form from lava, molten rock which has been thrust out of a volcano onto the surface of a rocky body such as an asteroid, planet, or dwarf planet.  

plutonic rocks are igneous rocks which form from subterranean chambers of molten rock or magma. plutonic rocks make up the base of continental crust as well as oceanic crust. their slow rate of formation causes them to be coarse grained since there is plenty of time for large crystals to form before the magma solidifies into rock.

the textural difference is that plutonic rocks are more coarse grained than volcanic rocks. plutonic rocks are coarse grained while volcanic are fine grained ; glassey or fragmental. since fine and coarse are adjectives the decision as to whether a rock is fine or coarse grained is generally made on the bases of whether or not the individual crystals can be seen in most if the rock.