The correct answer is - Theory of the Ekman spiral
V. W. Ekman or Vagn Walfrid Ekman was a Swedish physical oceanographer. He is famous for his studies of the dynamics of ocean currents. Ekman developed a theory called as the “theory of the Ekman spiral”. This theory explains maintaining balance between frictional effects in the ocean and the Coriolis force. The force arises from moving objects in a rotating environment such as planetary rotation. 
 
        
                    
             
        
        
        
D.) ovum. this is because haploid cells are present during mesois, which occurs in the reproductive organs. diploid cells are full counted cells which occurs in mitosis
        
             
        
        
        
Answer:
Taxonomy chart for plants (mango) is given below :
1) The domain is eukaryote. 
2) Kingdom is plantae. 
3) Division is embrophyta. 
4) Class is dicotyledonae. 
5) Order is sapindales. 
6) Family is anacardiaceae. 
7) Genus is magnifera. 
8) Specie is indica. 
Explanation: 
Eukaryote are those organisms having true nucleus. Dicotyledons are those plants in which seeds have two cotyledons. Mango plant belongs to Angiosperm i. e. seeds are hidden in the ovary. 
 
        
             
        
        
        
Answer:
The correct answer is Option d. They line up in the middle of the cell.
Explanation: 
Metaphase is a stage of mitosis in which condensation of DNA molecule into chromosomes occurs. During metaphase, nucleus is disappeared and chromosome becomes visible in the cytoplasm of the cell. There, the chromosomes line up in the middle of the cell.