Astudent poses the question: how does the presence of dissolved salt affect the freezing point of water? to answer this question, the student set up two conditions. in the first condition, the student added salt to water in a container and referred to this condition as the variable. in the second condition, the student did not add any salt to water in a second container and referred to this condition as the control. the student took both containers and attempted to freeze the water at various temperatures to assess the freezing point. would this be a valid experiment?
a. yes, because there is more than one variable. b. yes, because there is one variable and a controlc. no, because there is not more than one variabled. no because there is only one variable and a control

The answer is A.

Explanation:

The example experiment given in the question would be a valid experiment because there is more than one variable.

For an experiment to be valid, there have to be a dependent variable, an independent variable, a constant and a control aspect.

In the example, we can say that the independent variable which has the direct effect on the aspect that we are looking for, the freezing point, is the amount of salt in the water. Therefore the dependent variable is the freezing point which is the part being observed for any change. The constant can be the amount of water used because it is static and the control can be the temperature the mixtures are exposed to which does not change throughout the experiment.

Therefore the answer is option A.

I hope this anwer helps.

i think the answer is gold im not entirely sure

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.