Answer:
Explanation:
In endoplasmic reticulum, many folds leads to an increase in surface area for ribosomes to attach which allows for protein synthesis to occur at an efficient rate.
 mitochondria has two membrane, 
It has an inner membrane which is folded inside the other. The fold create cristae, which is the site for a portion of cellular respiration. 
The folds also enables a large surface area that makes chemical process to occur in an efficient way. 
 
        
             
        
        
        
Calcium ions presents Ca+ binds to troponin which makes tropomyosin move out of way for myosin to attach. Cross-bridge attaches. ATP breakdown provides energy to ready the myosin head for a power stroke. Myosin head attaches to exposed binding site on actin and the power stroke is accomplished. Cross-bridge (Myosin head) springs from raised position and pulls on the actin filament. Cross bridges break, ATP binds to Cross-bridge (but is not yet broken down) Myosin heads are released from actin. As long as calcium ions and ATP are present, this walking continues until the musle fiber is fully contracted. Hope this helps!
        
             
        
        
        
The answer;
 A combination pill
Explanation; 
Contraception entails methods that are used to prevent pregnancy. They include; hormonal methods, barrier methods and natural methods. A combination pill is a type of oral contraceptives that contain estrogen and a progestin. It keeps the ovaries of the female from releasing an egg. Different types of this pill contains different doses of estrogen and progestin.
        
             
        
        
        
It is separated by the endocardium !
        
             
        
        
        
Answer: there made up of carbon, oxygen, hydrogen, and nitrogen 
Explanation: I learNed it in science class