When cells communicate by the signaling process, one cell produces a signaling molecule that must be received by the signal receptor on or in the responding cell. Signaling molecules are often called ligands, a general term for molecules that bind specifically to other molecules (such as receptors).
Water (H
2O) is a polar inorganic compound that is at room temperature a tasteless and odorless liquid, which is nearly colorless apart from an inherent hint of blue. It is by far the most studied chemical compound and is described as the "universal solvent" [17][18] and the "solvent of life".[19] It is the most abundant substance on Earth[20] and the only common substance to exist as a solid, liquid, and gas on Earth's surface.[21] It is also the third most abundant molecule in the universe.[20]
Comparing DNA
Darwin could compare only the anatomy and embryos of living things. Today, scientists can compare their DNA. Similar DNA sequences are the strongest evidence for evolution from a common ancestor. Look at the diagram in Figure 9.3
Answer:
E. 3, 6, 7, 4, 5, 8, 1, 2
Explanation:
Systemic circulation is the circulatory pathway which is involved in the transport of the oxygenated blood to the body when pumped by the heart through arteries, capillaries and then back to the heart.
In the given question, the order of vessels in the systemic circulation has been asked which begins with the entry of the deoxygenated blood to the heart.
1. The deoxygenated blood enters the blood from vena cava to the right ventricle.
2. From the right ventricle, the blood enters the right atrium which pumps the de-oxygenated blood to the lungs through an artery called the pulmonary artery.
3. In the lungs, the blood becomes oxygen rich and is returned to the left atrium through the pulmonary vein.
4. The blood then enters the left atrium which is then pumped to the body through the main artery called the aorta.
This completes the systemic circulation and thus, Option-E is correct.
