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.
Answer:
The cuticle is the hair's protective layer, the cortex forms the pigment of the hair, the health of the cortex depends on the cuticle protecting it while the medulla is the innermost of the hair.
Explanation:
The cuticle is the hair outermost layer, the cortex is the middle structure for strength while medulla is the inner most.
Answer:
C. internal fertilization
Explanation:
The release of eggs and sperm into the water is known as spawning.
Gallons. You buy gasoline by the gallon.
