The correct answer to this question is this one: a.) bottleneck effect. Increased poaching nearly led to the extinction of the American bison. The kind of effect that does this example represent is called the bottleneck effect. Hope this helps answer your question.
Similar to the other types of muscle, smooth muscle contraction is caused by the sliding of myosin and actin filaments over each other. Calcium initiates contractions in a different way in a smooth muscle than in a skeletal muscle.
Smooth muscles use less energy to generate the given amount of force, can substain contractile force without fatigue & uses calcium from the sarcoplasic reticulum & extracellular space.
Mainly carbohydrates our body stored energy as glycogen.
Positive selection of t cells occur in .the thymus