Molecules can exist in free state because:
They are bigger in size as compared to atoms.
They are very stable.
They are very reactive.
They are electrically charged.
Molecules can exist in free state because they are very stable.
Micro-nutrients are needed in very small quantities because of which they are also known as trace elements.
Snakes are killed in large numbers because: (a) they are very poisonous (b) they kill rats (c) their skin is expensive (d) they damage the crops