Ionic bond is a compound made up of a meta and a non-metal eg NaCl (sodium chloride)
covalent bond is made up of two non-metals eg H2O (water)
A related or common origin or property of an element in the chemical bond.
The main function of the circulatory system is to move materials throughout the body, blood for cellular respiration, sugars for energy, leukocytes for immune support, and other nutrients necessary for proper homeostasis.
Aquatic animals would be it
Answer:
That is administered and controlled
Step-by-step explanation:
A variable is the condition or a product that may vary without the influence of any investigator. Such variables can be found abundantly in our daily lives, ranging from air to sunlight. Controlling such variables ensures the limitation of their influence on the outcome of an experiment. In connection to this experiment, the variables that are controlled are the mineral content in the water, the amount of bacteria food, the amount of light and the the constant temperature of 20 degrees C.
If not administered or these variables controlled, the experiment would not clearly explain the impact of caffeine on the heart beat of the water fleas as other variables may have influenced it. Thus variables are controlled to study the singular impact of any agent or effect.