Pigments absorb light used in photosynthesis.Set of wavelengths that a pigment doesn't absorb are reflected.
The natural rate of extinction as assumed by science is about 5 species per year. Currently scientists estimate we are losing species at 1000-10000 times that rate, with multiple species disappearing every day. A note on this idea is that the average extinction rate gives an unrealistic depiction of nature when we consider the catastrophic extinction events that ended the dinosaurs and shaped the ice age.
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.
