18) Have you ever noticed things move or change in nature without the help of a human? Think about patterns of ripples formed in
sand on the playground, and a hole or dip formed in soit under a rain gutter. What is the BEST explanation of how things like this
happen?
A)
Soitand-rocks make changes tech season like teaves on trees
B)
Water and/or wind make changes to soil and/or rocks over time
C)
Gravity causes dirt on the playground and under gutters to move
D)
The Moon causes rocks and soil to move, like the tides of oceans
16)
Which process causes hillsides and mountains to gradually get smaller?
-)
rch
O
Oop

B)

Explanation:

because the wind is moving the sand and the rain moves the soil

16) weathering and erosion

answer; /// the amount of material dissolved in a measure of liquid(concentration) the above statement is (true); /// good luck

- 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