The correct answer is D. Assent of the child and permission of both parents are required.
Explanation:
In any research study, it is required to ask for the assent of the participants, no matter if the risk is low, which is established by the Institutional Review Board or IRB that regulates ethics in research. This implies in the case presented, the assent of the child is necessary, especially because a medical procedure (additional bone marrow aspirates) will be performed, and this is related to risks.
Besides this, if the participant is a minor the permission of both parents or the legal is needed as the child might not have the maturity to decide whether to participate in the research study. Thus, the requirements are " Assent of the child and permission of both parents are required".
the mole concept :
a mole (mol) is defined as the amount of substance that contains as many atoms, molecules, icons, electrons or any other elementary entities as there are carbon atoms in exactly 12 gm of. the number of atoms in 12gm of is called Avogadro's number.
I'm not sure about muscular mass sorryyyy
Answer: 429 grams of 
should be added to 1.3 L of water to prepare 2.0 M solution
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
where,
n = moles of solute = 
= volume of solution in Liters
Now put all the given values in the formula of molarity, we get
Therefore, 429 grams of should be added to 1.3 L of water to prepare 2.0 M solution
Answer:
Go on the site named " the chemistry of ice cream ''
Explanation:
https://davidson.weizmann.ac.il/en/online/sciencepanorama/chemistry-ice-cream
Atomic mass = 39
number of neutrons = 20
Number of protons= 19
Electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1
The number of electron in first shell = 2
number of electrons in n=3 shell = 8
