Yasir wants to determine if there is a relationship between room color and sleep. Based on his research, Yasir makes an educated guess that people fall asleep more quickly in a room painted blue than in a room painted yellow. He asks several people which color they like better—yellow or blue—and uses their responses to determine if his educated guess was correct. What is missing from Yasir's scientific investigation? A. testable hypothesis based on research B. experiment that tests the hypothesis C. variables to be tested by an experiment D. research on the topic to see what others have learned

B). An Experiment that tests the hypothesis.

Explanation:

The element that is missing from Yasir's scientific investigation is 'an experiment which tests a hypothesis.' His experiment does not provide a verifiable statement revealing his proposition or prediction regarding the possible outcome of the experiment which could be verified by using a research or investigation. He rather tests his proposition indirectly by asking 'which color they like better' and using it to make an educated guess. Thus, option B is the correct answer.

hey your not cool]      

- 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