Explanation:
Scientists didnt belive that there are cells untill robert hooke (1665). He observed the cells in a cork slice with the help of a PRIMITIVE microscope
Leeuwenhoek (1674), with the help of an improved microscope, discovered free living cells in pound water for the first time. 
It was robert brown in (1831) who discovered the nucleus in the cell. 
Purkinjie in 1839 coined the term 'protoplasm' for the fluid substance of the cell. 
THE CELL THEORY, that all plants and animals are composed of cells and that the cell is the basic unit of life, was presented by two biologists, schleiden (1838) and schwann(1839). The cell theory was fuether expanded by virchow (1855) by suggesting that all cells aris form PRE-EXISTING cells. With the discovery of the electron microscope in 1940,it was possible to observe and understand the complex structure of the cell and its various organelles. 
Well, thats the history of the discovery of cells. 
 
        
             
        
        
        
Answer:
Theoretically, competition can initiate divergence in habitat use between individuals of a species, leading to restricted gene flow and eventual speciation. Evidence that sister species differ in habitat use is commonplace and consistent with this mechanism, but empirical experimental support is surprisingly scarce.
 
        
             
        
        
        
A single gene disorder is one that's known to be caused by a single gene. Multiple gene disorders, however, can be caused by multiple gene combinations and other factors. Dominant genes are always expressed in the offspring, while recessive genes are only expressed if the offspring recieves the recessive gene from both parents. Sex-linked genetic disorders occur most often in men, and are caused by a single-gene disorder gene being on the X chromosome but not the Y, so that the offspring needs only one recessive gene to have the trait/disorder.
Does this help? Any more questions?
        
             
        
        
        
Answer:
 A
Explanation:
The N (2.2 N) is Newton. Newton is weight.
 
        
             
        
        
        
Answer:
Option A Fruit
Explanation:
After fertilisation, the female parts of the flower develop into a fruit: the ovary wall becomes the rest of the fruit.