The haemoglobin content per 100 ml of blood of a normal healthy human adult is

Given below are four statements (i-iv) regarding human blood circulatory system.
(i)  Arteries are thick-walled and have narrow lumen as compared to veins.
(ii)  Angina is acute chest pain when the blood circulation to the brain is reduced.
(iii)  Persons with blood group AB can donate blood to any person with any blood group under ABO system.
(iv)  Calcium ions play a very important role in blood clotting.
Which two of the above statements are correct?

Fastest distribution of some injectible material/medicine and with no risk of any kind can be achieved by injecting it into the

Root development is promoted by