Answer:
smooth endoplasmic reticulum
Explanation:
Smooth endoplasmic reticulum differs from the rough endoplasmic reticulum in not having ribosomes on its surface. The smooth endoplasmic reticulum (SER) extends from the rough ER and forms a network of membrane tubules. The function of the smooth ER is to serve as a site for the synthesis of lipids, fatty acids, and steroids such as estrogens and testosterone. 
Enzymes for the synthesis of these diverse biomolecules are present in smooth ER. The smooth ER present in the muscle cells is called the sarcoplasmic reticulum. It stores the calcium ions which are released into the sarcoplasm of muscle cells during muscle contraction. 
 
        
             
        
        
        
Answer:
The given statement is false. 
Explanation:
The mammals can be differentiated into three main groups on the basis of the development of their babies. These three groups are marsupials, monotremes, and placental mammals, which is the largest group. The monotremes refer to the mammals, which lay eggs. The marsupials refer to the mammals, which give birth to young ones that are not developed completely. While in a placental mammal, the development takes place within the body of a mother until and unless its systems of the body start to work on their own.
 
        
             
        
        
        
The excretory and urinary are not the same because the excretory system is collective for all system performing the function of eliminating waste from the body like excess water,urea, carbon dioxide and lactic acid but the urinary system focuses on removal of excess water and urea from the body