Answer:
a group of organs working together to perform a function.
Explanation:
Answer:
A fair test.
Explanation:
Hi, a fair test is used to do scientifically valuable experiments, is a controlled investigation to answer a scientific question.
In a fair test two or more things are compared.
It consists in changing only one factor (the one bieng tested) and keeping all the other conditions the same during an experiment.
The factor is called a variable.
Chemical change is any change that results in the formation of new chemical substances. At the molecular level, chemical change involves making or breaking of bonds between atoms. These changes are chemical: iron rusting (iron oxide forms) gasoline burning (water vapor and carbon dioxide form)
Sodium (Na) is a Alkali metal so that's the answer
