Specialized tissue on the wall between the atria. Electrical impulses pass from the pacemaker (SA node) through the _______ and the atrioventricular bundle (bundle of His) toward the ventricles.atrium (pl. atria)One of two upper chambers of the heart.capillary<span>Smallest blood vessel. Materials pass to and from the bloodstream through the thin walls. They have walls that are only one endothelial cell in thickness. This delicate, microscopic vessel carries nutrient-rich, oxygenated blood from the arteries and arterioles to the body cells. There, the nutrients are burned in the presence of oxygen (catabolism) to release energy.
At the same time, waste products such as carbon dioxide and water pass out of the cells and into these blood vessels. Waste-filled blood then flows back to the heart in small venues, which combine to form larger vessels called veins.</span>carbon dioxideGas (waste) released by body cells, transported via veins to the heart, and then to the lungs for exhalation.coronary arteriesBlood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle.deoxygenated bloodBlood that is oxygen-poor.diastole<span>Relaxation phase of the heartbeat.</span>
Idk sorry i need 2 more points!
A flagella helps an animal sperm move!
1. <span>composed of cells with cell walls
2. </span><span>Vertebrates contain a backbone, while invertebrates do not.</span>
Answer:
Scientists have discovered what they say could be fossils of some of the earliest living organisms on Earth. They are represented by tiny filaments, knobs and tubes in Canadian rocks dated to be up to 4.28 billion years old.
Explanation:
