The correct answer is option 2: 2 and 3 only.
This means that red blood cells (option 2) and platelets (option 3) are the cells that do not contain a nucleus.
1. Root hair cells (option 1) contain a nucleus. Root hair cells are found in plants and play a role in absorbing water and minerals from the soil. They have a nucleus to carry out their functions.
2. Red blood cells (option 2) do not contain a nucleus. This is because during their development, the nucleus is expelled to make more room for hemoglobin, the protein that carries oxygen. Without a nucleus, red blood cells are more flexible and can easily travel through tiny blood vessels.
3. Platelets (option 3) also do not contain a nucleus. Platelets are cell fragments involved in blood clotting. Like red blood cells, platelets discard their nucleus as they mature.
4. Monocytes (option 4) do contain a nucleus. Monocytes are a type of white blood cell and are part of the immune system. They have a nucleus to carry out their various functions, such as identifying and engulfing pathogens.
Therefore, the correct answer is option 2 as red blood cells and