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.

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.

c: warm water flows from the western tropical pacific toward south america. that should be the right answer! hope it .