He will let CO2 out also when he poops he lets out CO2 too.
Answer:
2)
Explanation:
The positive control is the treatment where bacteria grew without lead. Since positive control indicates the presence of bacteria in the experimental conditions, it is possible to confirm that they only death in presence of this metal. However, it is important to note that it is imperative to repeat this experiment three times and also to include a negative control in order to confirm these results.
There's a bunch of examples.
For example, hairlines. A widow's peak is a dominant trait over a straigh hairline.
Or dominant hand type. Right hands are dominated over left hands.
Or hair types. Curly hair dominates straight hair.
If you google it, you'll get a lot more examples.