True, False , and I think the last one is true
A solution may exist in any phase so your answer is D. any of the above
hope this helps :)
Answer:
True.
Explanation:
Iodine is an essential element required for the synthesis of Thyroxine is a correct statement.
Iodine is an essential and controlling medium for thyroid hormone production, as a minor ingredient. It is an important element in the development of thyroid hormones thyroxine (T4) and triiodothyronine (T3) by the thyroid gland.
Answer: a) Temperature of 
b) 
c) dehydrating agent
Explanation:
Ethanol is heated with an excess of concentrated sulfuric acid at a temperature of 170°C to produce ethene.
The balanced chemical reaction is:
Here concentrated sulfuric acid removes a water molecule from ethanol and thus acts as a dehydrating agent.
The valves stop the blood from flowing backwards
