Questions

Blood is a heterogeneous mixture because the blood cells are physically separate from the blood plasma. The cells have different properties than the plasma. The cells can be separated from the plasma by centrifuging, which is a physical change.

Senior IPS officer Alok Kumar Verma, Delhi Police Commissioner was appointed as new Director of the Central Bureau of Investigation. He will have tenure of two years. He was selected by a three-member committee comprising Prime Minister Narendra Modi, Chief Justice J S Khehar and Congress leader Mallikarjun Kharge. He will take over from interim director Rakesh Asthana, who was handed the reins of the premier investigating agency after former director Anil Sinha retired on December 2, 2016.

Veins are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to veins, arteries carry blood away from the heart.

Veins are less muscular than arteries and are often closer to the skin. There are valves in most veins to prevent backflow.