Geographic barriers can prevent the migration of individuals between populations. However, an effective barrier for one species will not necessarily be an effective barrier for a different species. True False

1. Ge necestan preparar a Kg de nitrógeno, medidas e \( 20^{\circ} \mathrm{C} \) y a una presión de 710 mimitig. La reaccion que se van a utilizar es. NH4Cl \( +\mathrm{NaNO}_{2} \rightarrow \mathrm{NaCl}+\mathrm{H}_{2} \mathrm{O}+\mathrm{N}_{2} \) ¿Cuántos gramos cloruro amónico deberemos emplear?

(iii) \( \left\{\begin{aligned} x_{1}-5 x_{2}-x_{3}+12 x_{4}-x_{5} & =-4 \\ -2 x_{1}+10 x_{2}+3 x_{3}-33 x_{4}+2 x_{5}+x_{6} & =4 \\ x_{3}-9 x_{4}+x_{5} & =8 \\ x_{1}-5 x_{2}+2 x_{3}-15 x_{4}+2 x_{5}+x_{6} & =14\end{aligned}\right. \)

Resolven to divisiós \( \left.6 x^{4}-2 x^{3}+x-1\right):\left(x^{3}-2\right) \)

9) \( \left(\frac{3}{2}\right)^{3}-\left(\frac{1}{4}\right)^{2}= \) a) \( \frac{-26}{8} \) b) \( \frac{28}{24} \) c) \( \frac{53}{16} \) d)

2. The school coach decides to have each student throw 2 table tennis balls instead of one. Explain how this will affect the number of packs needed.