Examples of physical changes in properties are melting, transition to a gas, crystallization, etc
The wall of the heart<span> consists of three </span>layers<span>: the epicardium (external </span>layer<span>), the myocardium (middle </span>layer<span>) and the endocardium (inner </span>layer<span>). The epicardium is the thin, transparent </span>outer layer<span> of the wall and is composed of delicate connective tissue.
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Explanation:
base on which an organism lives the soil is the substrate of most seed plants. .A substance acted upon (as by an enzyme)
Since people with HIV have weakened immune systems it would be:
C) People with HIV are unable to fight off these rare diseases.
