Answer:
Poriferans.
Explanation:
The evolution of the organisms has been occur from the simple organisms and leads to the evolution of the more complex organisms. This complexity arises due to the changing environment of the organisms.
The protozoans are the simplest organisms and all the other animal lineage has been derived from the porifera. The porifera are the cellular organisms that  do not have tissue level of organization and simple physiological system. Later, diverse and complex organisms arise from the porifera.
Thus, the correct answer is option (1).
 
        
             
        
        
        
The Nucleus is the hub of the cell, the heart and soul of the cell. As much as a quarterback is in a football team. The Nucleus is what keeps the cell going and a cell wouldn't exist without a Nucleus. Hope this helped, have an amazing day :)
        
                    
             
        
        
        
Hydrogen bond ! this hold water ( and other molecules with high polarity ) together !
        
             
        
        
        
Answer:
Electron transport chain and chemiosmosis/ oxidative phosphorylation
        
                    
             
        
        
        
Answer:
Incorrect
Explanation:
In the bone modelling process, osteoblasts a responsible for bone formation and osteoclasts are responsible for bone resorption. In the young adult during growth, the formation of bone exceeds the resorption of bone to maintain bone mass. Therefore, 
As we get older, bone formation decreases due to reduction in osteoblastic activity and numbers and bone resorption increases as a result of sex hormone deprivation, this will result in decreased bone mass (osteoporosis). Therefore, osteoclastic activity would have to exceed osteoblastic activity in order or osteoporosis to develop