Does the size of oxygen molecules and carbon dioxide molecules support the claim that masks that block a viral particle will also block the passage of oxygen and carbon dioxide molecules? Explain the reasons for your answer.

Polar bears give birth and hunt on sea ice. which of the following would polar bears survive during the melting of arctic ice? growing another layer of fur during summer migrate inland to search for different food sources staying put until the ice refreezes sticking to the usual diet of seals