Which of the following is not an example of pseudoscience? a. vaccines b. healing crystals c. psychics d. acupuncture

The correct answer is A. Vaccines.

Explanation

A pseudoscience is a discipline that is presented as scientific although it is not recognized as such by the traditional scientific community. Pseudosciences generally have objects of study that prevent them from fully applying conventional scientific methods. Also, they lack an explanation for some phenomena so it is not considered by the scientific community as a producer of new objective knowledge. According to the above, vaccines are the correct answer because they are the product of scientific research and various tests. So, the correct answer is A. Vaccines.

- 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