Answer:
Osteoclasts are the type of cells which are responsible for the absorption of calcium from bones. 
Explanation:
Osteoclasts is special type of cells which is released by parathyroid gland when the blood have low levels of calcium. Osteoclasts absorb calcium from the bones and add this calcium into the blood to increase the calcium level. If calcium is present in very high amount so this calcium is stored in the bones of the body and extracted when needed by the body. 
 
        
             
        
        
        
The given statement "Decreasing the rate of gene flow between two populations is likely to make the populations more different from one another." is False.
<h3>
What is gene flow?</h3>
- Gene flow refers to the processes by which genes are transferred from one group to another. 
- Gene flow, which is a term used more frequently in anthropology, refers to the allelic change brought on by human movement. 
- Gene flow would reduce the isolation that could lead to speciation by increasing population similarity and reproductive kinship. 
- Gene flow significantly slows down speciation by recombining the gene pools of the groups and therefore repairing the growing variations in genetic variation that would have otherwise resulted in full speciation and the creation of daughter species.
Learn more about the gene flow with the help of the given link:
brainly.com/question/17190749
#SPJ4
 
        
             
        
        
        
Work done= <span>force x distance moved in the direction of that force so: 200 x 15 = 3000J=4kJ</span>
        
             
        
        
        
In this case, the black body colour is the dominant one. The white dog is  homozygous recessive.
As the cross between the black female 2 and the white male results in all black pups. This means that the all the offsprings are heterozygotes and the Female 1 is homozygous recessive having a BB phenotype (where B codes for dominant allele). 
As the cross between the black female and the white male results in four white and three black pups. This means that the all the black offsprings are heterozygotes, and the white ones are homozygous recessive and the Female 2 have a dominant and 1 recessive gene, and is a hetrozygotezygous recessive having a Bb phenotype (where B codes for dominant allele and b codes for recessive allele). 
 
        
             
        
        
        
Answer:
You did not write the concept, so i will try to answer in a general way.
Why sometimes we really need to model concepts?
Well, sometimes the things are really complicated, or we just do not have the knowledge or tools to fully understand them.
Here is where the models came to be handy, we can somewhat "simplify" the things, and explain them with models.
For example, the movement of a particle as the wind pushes it can be really complex, so this can only be explained with a model.
Now, once we have a model (supported by theory and experiments) we can start to investigating furthermore in the given subject.
So for example, we could model how a given therapy acts on a given disease, and with that model, we could extrapolate the effects of the therapy in a similar disease (for example, testing how radiotherapy acts on a given tumor in some organ, can give information on how the same therapy can act on other types of tumors)
Concluding, models simplify some concepts, which allow us to understand them and work better with them