All that is needed is a warmer, lighter fluid below a cooler, heavier one.
Since warm water is lighter, it will rise, and will cool from the top will flow down to replace it, this makes it go in motion
        
             
        
        
        
Answer: 3.friction
Explanation: friction is a force of resistance acting between objects in contact and tending to dampen their motion
 
        
                    
             
        
        
        
Answer:
Genetic drift is a mechanism of evolution in which allele frequencies of a population change over generations due to chance (sampling error).
Genetic drift occurs in all populations of non-infinite size, but its effects are strongest in small populations.
Genetic drift may result in the loss of some alleles (including beneficial ones) and the fixation.
Genetic drift can have major effects when a population is sharply reduced in size by a natural disaster (bottleneck effect) or when a small group splits off from the main population to found a colony (founder effect).
 
        
             
        
        
        
I’m not entirely sure about what you’re asking but chargaff’s rule is the thing that states that the amount of each “letter” in DNA is equal to its pair. Guanine (g) pairs with cytosine (C) and the same with adenine(A) and thymine (T). I’m sorry my answer is so vague, but I hope it helps a little!
        
             
        
        
        
Answer:
Every living thing plays a role in the food chain and Earth's ecosystems, and the extinction of certain species, whether predators or prey, can leave behind significant impacts. ... “When a predator goes extinct, all of its prey are released from that predation pressure, and they may have big impacts on ecosystems.”
Explanation: