20. The answer is 1 (Precambrian)
21. The answer is 4 (Pennsylvanian)
22. The answer is 2 (Bony Fishes, Dinosaurs, and Mammals)
23. The answer is 2 (Reptiles)
<em>MARK</em><em> </em><em>ME</em><em> </em><em>BRAINLIEST</em>
Answer:
- Continuous cultivation of crops in soil leads to the depletion of certain nutrients.
- If these nutrients are not replenished, soil becomes sterile and unfit for cultivation.
Answer:
Hello.
• gels can melt during electrophoresis, the buffer can become exhausted, and different forms of genetic material may run in unpredictable forms.
• And the strengths could be that it separates based on size, it is relatively easy to do.
Contractions and water breaking!! Hope this helps.
