Why does a mask have to cover both your nose and mouth to be effective explain using the Respiratory tract

Which of these is the most likely consequence of falling petroleum price

Look at the picture below . what does this picture represent ?

4the indian leaf butterfly has traits that allow it to resemble a leaf. the bright colors of the monarch butterfly indicate that the butterfly tastes bad and can be poisonous. how does the appearance of these butterflies them to survive? f the indian leaf butterfly is able to avoid predators while the monarch butterfly warns predators away. g. the indian leaf butterfly frightens predators away while the monarch butterfly poisons predators before they can eat it. h both butterflies rely on camouflage to avoid predation. j both butterflies cooperate with one another to avoid predation.