Read this scenario, and then answer the questions that follow. Human transportation enabled a species of beetle to move from Asia to North America. This beetle feeds on a particular species of flowering trees. In its native habitat, predators control its population. However, the beetle has fewer predators in North America.

A group of scientists studied the effect this beetle has on the tree population in the forest. After five years of research, they determined that the beetle population doubled each year. On the other hand, the number of healthy trees decreased by 40 percent from the previous year’s population. During the first year of their research, the scientists estimated that there were 250 beetles and 4,000 healthy trees in the forest area.

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

answer: a tank of height h is filled with water and sits on the ground. water squirts from a hole at a height y above the ground and has a range r. for two y values, 0 and h, r is zero. determine the value of y for which the range will be a maximum.

explanation: