Answer:
<u>A common element among all the river valley civilizations was irrigation systems that moved water to crops and settlements</u>
Explanation:
- <u>River Valley civilizations where the civilizations that were found on the banks of the river like the Mesopotamia ,Indus valley civilization.</u>
- <u>These civilization where agriculture based civilization as they depended on river for drinking water and irrigational activities</u>
D. Mutations involved the genetic variation of the bugs are random
B.https://www.mansfieldct.org/Schools/MMS/staff/hand/genNaturalselection06.htm this is where I got my source.
Prokaryotes reproduce asexually by binary fission; they can also exchange genetic material by transformation, transduction, and conjugation.
Overlapping niches lead to competition because they need the same resources such as food sources
