17.it can be said that vaccines do not actually prevent infection. using information learned in previous activities, explain this statement.

Vaccines don't prevent infection it just helps your body to know how to fight a certain infection if/when it enter the body. A vaccine gives your body a tiny amount of a certain antigen so that the body can find the right way to fight it and keep some memory b cells to fight it if the need should arise. Say a person has been vaccinated against the flu and that strain enters their body, they still have it but there body has already seen it and can fight the infection off (hopefully) before you get sick and notice any symptoms.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.