Biogenic elements
Answers are for parents and teachers.
1
If 10 % of a 70 kg person’s body is hydrogen, what is its mass?
7 kg
2
If 1 g of salt holds 30 µg of iodine, how many µg do 5 g give?
150 µg
3
Which element is in haemoglobin and what is its role?
Iron; carrying oxygen.
4
What sign appears in a plant with an iron deficiency?
Leaves turn yellow (chlorosis).
5
Why is “the more I take the better” wrong for vitamins?
An excess poisons; the dose matters and a doctor decides.