Explanation:
biotic factors are the things which have life like animals and plants
And Abiotic factors are the things which don't have life like air,stone and river
Answer:
Gallium-72
Explanation:
The elements are identified by the number of protons of the atom, which is its atomic number.
In this case the number of protons 39 (atomic number 39) permit you to identify the element as gallium.
Now, to identify the isotope you tell the name of the element and add the mass number.
The mass number is the sum of the protons and the neutrons
In this case, the number of neutrons is the original 39 plus the 2 added suddenly, i.e. 39 + 2 = 41, so the mass number is 31 + 41 = 72
Therefore, the isotope is gallium - 72.
The statement that best describes the variables in a controlled experiment is independent variable while all other conditions are unchanged.
<h3>What is an experiment?</h3>
An experiment is a scientific research, findings or investigation about a subject matter with the aim of validating a claim and establishing theories.
A controlled experiment refers to an experiment in which the variables involved and the control factor are kept in the same group except for one variable which can be changed.
Therefore, The statement that best describes the variables in a controlled experiment is independent variable while all other conditions are unchanged.
Learn more about experiment below.
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