Why is it possible to float a small paperclip very carefully on top of water? (2 points)

hydrogen bonds between water molecules create surface tension.

unpaired electrons on water molecules at the surface create surface tension.

only water close to freezing and denser than usual will have enough surface tension.

covalent bonds between the hydrogen and oxygen of water molecules create surface tension.

The correct answer will be option-Hydrogen bonds between water molecules create surface tension.

Explanation:

The water is made up of water molecules which are bonded to each other thorough hydrogen bonds but at the surface of the water , the water molecules do not have the extra molecules to bind.  

This causes more tension between water molecules and cause large cohesion between the water molecules at the surface due to which it forms an invisible thin film at the surface. It is known as surface tension.

The surface tension causes the paper clip to float on water and therefore selected option is the correct answer.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.