Here are four sketches of substances. Each sketch is drawn as if a sample of the substance were under a microscope so powerful that individual atoms could be seen. Decide whether each sketch shows a sample of an element, a compound, or a mixture. \begin{tabular}{|c|c|} \hline Substance X & Substance \( Y \) \\ \hline & \\ \hline O element & O element \\ \hline compound & ompound \\ \hline mixture & mixture \\ \hline Substance Z & Substance T \\ \hline & \\ \hline O element & O element \\ \hline compound & compound \\ \hline mixture & mixture \\ \hline \end{tabular}

15. \( \lim _{x \rightarrow 1} \frac{(2 x-3)(\sqrt{x}-1)}{\left(2 x^{2}+x-3\right)} \)

Solve for \( x \quad q^{(x+b)}=P \)

Which expression equals \( 7 \times 7 \) ? \( \begin{array}{l}7+7+7+7+7 \\ 7+7+7+7+7+7 \\ 7+7+7+7+7+7+7 \\ 7+7+7+7+7+7+7+7\end{array} \) \( \begin{array}{l}7\end{array} \)

16: Functional Organization of the Endocrine System True or False? Damage to filiform papillae would disrupt a person's sense of taste for sweet substances. Select one: True False

112 Una produzione di olio può essere immessa sul mercato in 420 bottiglie da mezzo litro. Se, in alternativa, si utilizzassero delle bottiglie da tre quarti di litro ( \( 0,75 \mathrm{~L} \) ) quante bottiglie servirebbe ordinare? Calcola il valore della co- stante di proporzionalita. [280; 210\( ] \)