Bright colors such as flowers or light green bushes/trees would result in an decrease in a blackbirds population because the blackbird wouldn't be able to blend into its environment due to the dark color it has, allowing many predators to spot it. So brighter colored environments would result in the decrease of the blackbird population.
The heart has an intrinsic conduction system that causes electrical activity in the heart muscles causing them to contract. The intrinsic conduction system is made up specialized cells, that contain nerve and muscular characteristics.
The muscle cells in the heart are linked together by gap junctions, allowing cardiac action potentials to travel from one muscle cell to another.
Atrioventricular (AV) node. The damage to the AV node causes the electrical signals traveling from the upper chambers to the lower chambers to be impaired causing an AV block.
