In a study, the independent variable is the thing that you change to see how the change produces different results. In this study, the independent variable would be the use of nicotine.
Epinephrine is the answer you're looking for. A more common and more used terms would be adrenaline.
Adrenaline causes immediate changes in your body during the alarm stage
Exoskeleton and Endoskeleton
Multicellular organisms e.g. man meet their needs through use of specialized systems that they have in their bodies. Examples of such include:
1. cardiovascular system composed of heart, veins and arteries which facilitate transport of nutrients to all parts of the body .
2. Skeletal system composed of bones, joints, ligaments and cartilage whose function is support and protection of the body. <span>
3. Digestive system composed of mouth, esophagus, stomach , small and large intestines whose function is breakdown of food and absorption of nutrients.</span>
The main factors affecting birth are:
Age.
Health.
Heredity.
Ovulation cycle.
Location.
Miscarriage