Removal of the tarnish from the silver is a <u>physical change</u>.
<h2>Explanation:</h2>
The type of change which doesn't produce any new substance is called as physical change. Tarnish refers to the thin black layer that is formed on the silver. Formation of tarnish is chemical change as due to oxidation a black color layer is formed.
On the other hand, removal of tarnish from silver is considered as physical change as no new product is formed and only we are obtaining the silver in its pure form.
The two important features that characterize the adaptive immune system are specificity and memory.
The ability of the adaptive immune system to target specific pathogen and generate a tailored immune response against it is termed as specificity.
The ability of the adaptive immune system to remember the first exposure to the pathogen and thus, generate a heightened and more rapid immune response against the same pathogen on subsequent exposure is termed as memory.
