*Question*
You are presented with the question "How long can antibodies protect the body?" and the following answer choices: - As long as antibodies survive - Slowing the transfer of heat - For a set time - by keeping them warm - it protects them - Into elderly years - As long as the human survives - A compound that donates proton Now knowing that passive immunity lasts only as long as the antibodies survive in body fluids and antibodies are administered to the patient in a process called passive immunization, choose the best answer.
**Answer**
As long as antibodies survive

*Question*
You are presented with the question "What harms the respiratory system?" and the following answer choices: - coal - oxygen - tar - cigars - breathing - silence - sulfur - cars Now knowing that air pollution harms the respiratory and circulatory systems and air pollution, or smog, is caused by cars and trucks, choose the best answer.
**Answer**
cars

*Question*
You are presented with the question "what can only contract?" and the following answer choices: - nerves - Epidermis - the skin - strong - biceps - Bend - lungs - forces Now knowing that muscles can only contract and muscles in the upper arm called biceps are used to flex the arm, choose the best answer.
**Answer**
biceps

*Question*
You are presented with the question "What can polar bears do to generate heat?" and the following answer choices: - make fire - eat ice - stay warm - nothing - fur - motors - shiver - sweating Now knowing that mammals can also generate little bursts of heat by shivering and polar bears are mammals, choose the best answer.
**Answer**
shiver