hiii, help and thanks :D

Read the questions carefully and write the letter of the correct answer in your answer sheet.
1.) Which of the following elements helps prevent rickets in children, softening of bones and decrease in bone mass in adults?
2.) Which of the following statements is TRUE about compounds?
3.) Which element is named based on astronomical object?
4.) How many atoms of hydrogen are there in water molecule (H20)?
5.) Which of the following is represented by chemical formula?
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