Answer is 3 it uses chemical and physical changes when using stomach acid and physical when turning food in your stomach.
Answer:
Radioactive labeling is a procedure used to monitor the path followed by a chemical element within a biological system to demonstrate the source.
Hypothesis:
The free oxygen produced during photosynthesis comes from water.
Procedure.
Single-celled algae were placed in four petri dishes containing carbon dioxide, glucose dissolved in Water.
In each box the oxygen was radioactively marked.
1 petri dish with CO2 marked. Experimental groups
2 petri dish with H2O marked. Experimental groups
3 petri dish with Glucose marked. Experimental groups (control)
4 petri dish with CO2 + H2O + Glucose, all marked. (control).
B 1/4 because i seen the question and answer on my test and got it correct
Answer: False
Explanation: This is FALSE because the bats make a high frequency sound and we can't hear that type of sound.