b. The placenta passes oxygen, nutrients, and other useful substances from the mother to the fetus.
c. The placenta mixes blood from the mother and fetus together.
d. The placenta protects the mother from being attacked by the fetal immune system.
Argon is a chemical element which is a gas at room temperature, has 8 valence electrons and 22 neutrons. This element belongs to the noble gas elements group.
Noble gas is any of the rare gases that include helium, neon, argon, krypton, xenon, and sometimes radon also and that exhibit great stability and extremely low reaction rates than other elements in the periodic table.
Argon is a chemical element with the symbol Ar and it has an atomic number of 18. It is in the group 18 of the periodic table and it is a noble gas. Argon is the third-most abundant gas in the Earth's atmosphere, at 0.9340 ppmv. It is more than twice as abundant as that of water vapor, 23 times as abundant as carbon dioxide, and more than 500 times as abundant as neon gas. Argon is the most abundant noble gas in the Earth's crust, which comprises about 0.00015% of the crust.
Learn more about Argon here:
#SPJ2
Answer:
Argon
Explanation:
The properties of a compound can often be predicted from the properties of its constituent elements, however, they're not always the same due to changes that occur during chemical reactions.
Yes, you can often predict the properties of a compound by knowing the properties of the elements that make it up. This is a fundamental concept in chemistry. For instance, sodium is a very reactive metal and chlorine is a poisonous gas, but when they combine to form sodium chloride, the resulting compound is ordinary table salt, which is safe to consume. However, it's important to note that while the properties of a compound are related to the properties of its constituent elements, they are not always the same. This is due to the changes that occur during the chemical reaction process, in which bonds are formed or broken and electrons are shared, gained, or lost.
#SPJ3
a
Answer:
Growth and Development.
Explanation:
.