Answer:
Red blood cells are adapted to their function by:
1) They contain haemoglobin - a red protein that combines with oxygen. they have no nucleus so they can contain more haemoglobin.
2) They are small and flexible so that they can fit through narrow blood vessels.
3) They have a biconcave shape (flattened disc shape) to maximise their surface area for oxygen absorption.
Hope this helps! :D
I think its A. If you had options like mine
The answer is A//////////
1. molecul of DNA 2. dna packed (coild) around histon h1 3.second stage of dna packing -solenoid thread 4. third stage of packing-chromosomal thread 5.chromosome-chromosomal threads are packed inside