Answer: iron (oxides of iron)
Explanation: manganese nodules usually contain layers of iron and manganese oxides in a concentric arrangement and are called polymetallic nodules.
Answer:
The correct option is;
c. the bone contains calcium salts, which are less reactive than the calcium ions found in the blood.
Explanation:
The most abundant metallic element found in the human body is calcium as it is present in the bones teeth and metabolism of the kidney
99 % of the calcium in the human body are found in the bones while the remaining 1 % circulates in the blood as ions
The bones of the vertebrate are made up of calcium salts such as calcium carbonate, calcium phosphate and calcium fluoride.
