State whether the following statement is true or false:
$A$ compound is a substance composed of two or more elements,chemically combined with one another in a fixed proportion.

What are the favourable qualities given to gold when it is alloyed with copper or silver for the purpose of making ornaments?

Priya's mother uses iodised salt at home. One day while cooking,Priya asked her mother about iodised salt. She said people who do not use iodised salt suffer from deficiency of iodine which leads to goitre and hypothyroidism.
$(a)$ What are the physical symptoms of goitre and hypothyroidism?
$(b)$ How will you inform others about the importance of iodised salt?
$(c)$ Is iodine a metal or a non-metal?
$(d)$ What are the physical properties of iodine?
$(e)$ What is the difference between iodised salt and normal salt?

Which of the following is an element?

When is a compound said to be pure?

Why is blood a mixture and graphite an element? Mention any one reason for each.