Who developed the first fabricated obturator? a. paré b. vesalius c. the romans d. fauchard

I believe the correct answer is option A. Paré.

Or otherwise known as Ambroise Paré. He was considered one of the "fathers of surgery" for modern forensic pathology. And was known to be a pioneer in surgical techniques on the battlefield using medicine, mostly in the treatment/healing of wounds.

Hope I could help! :)

- 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