Answer:
penicillin could protect mice against infection from deadly Streptococci.
Explanation:
Answer:
C. Y & Z
Explanation:
V, W are imaginary metals here because their valence electrons are typically less than 4. X, Y, Z are non-metals and have higher valence electrons. Here, if V or W bind with X, Y, or Z we make ionic bond (because metal + non metal = ionic). But, if X binds with Y or Z or any combinations of any two of the three non-metals results in covalent bond (non metal + non metal = covalent).
Thus, Y and Z make covalent.
Only one of the listed choices are correct here:
<span><em>The x-axis would change title and values.</em>
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Mass of CaCl₂ = 0.732 g
<h3>Further explanation</h3>
The concentration of a substance can be expressed in several quantities such as moles, percent (%) weight / volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.

It's an ionic bond! Potassium is a cation, or a metal with a positive charge, and fluoride is an anion, or a nonmetal with a negative charge.
A covalent bond is the bond between two nonmetals.
Hope this helped!