When did pangaea begin to break apart?
a. 20 million years ago
c. 250 million years ago
b. 100 million years ago
d. 2 billion years ago.

Answer;

250 million years ago

Explanation;

-In early geologic time, Pangea was a supercontinent that incorporated almost all the landmasses on Earth.

Pangea was surrounded by a global ocean called Panthalassa, and it was fully assembled by the Early Permian Epoch.

The supercontinent began to break apart about 200 million years ago, during the Early Jurassic Epoch, eventually forming the modern continents and the Atlantic and Indian oceans.

icc, international association for cereal chemistry

- 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