"Life is learning" and "society is teaching material". Chemistry is increasingly reflecting its autonomy in aspects such as food, clothing, housing and transportation, environment and energy, materials science, and medical and health care.

(1) Sesame paste is rich in nutrients. Figure 1 shows a part of the trademark of a certain brand of sesame paste. Among them, calcium, iron, and selenium refer to compounds containing calcium, iron, and selenium elements; so the answer is: D;

(2) Aluminum reacts with oxygen in the air to form alumina, and the reaction The chemical equation is: 4Al 3O2═2Al2O3; so the answer is: 4Al 3O2═2Al2O3;

(3) ①The recyclable metal materials in the battery include copper and zinc; so the answer is: copper;

②Extract manganese dioxide: remove a small amount of carbon powder in manganese dioxide. The carbon powder can react with oxygen to generate carbon dioxide gas, but manganese dioxide cannot burn; so the answer is: ignite in oxygen;

(4) ① Since the oxygen in the teacup is depleted when the candle burns, there is no oxygen in the teacup, and the candle goes out due to lack of oxygen; therefore the answer is: the oxygen is exhausted, and the candle goes out due to lack of oxygen;

② When a candle burns, it generates a lot of heat. The temperature of the generated carbon dioxide rises, and the airflow rises and gathers in the upper part, causing the taller candle to go out first; so the answer is:;

③Student B thinks that the lower candle The lower candle is extinguished first. This is because carbon dioxide is denser than air and is deposited below, causing the lower candle to extinguish first. Therefore, the answer is:;

A. The inner wall of the tea cup was observed to turn black through the experiment, indicating that the substance A large amount of smoke is produced during combustion, so cover your nose with a towel to filter it; therefore A is correct;

B. It is concluded from the experiment that the carbon dioxide and harmful gases produced by combustion accumulate due to high temperatures. At the top, so B is wrong;

C. Since the carbon dioxide and harmful gases produced by combustion are gathered at the top due to the higher temperature, there are less harmful gases in the lower air; so C is correct. ;

D. If you open the window and jump out, it is easy to fall to death; therefore D is wrong;

So the answer is: AC.