Answer:
A. there is an isotope of lanthanum with an atomic mass of 138.9
Explanation:
By knowing the different atomic masses of both Lanthanum atoms, we can not tell anything about their occurence in nature. Therefore, all the last three options are incorrect. Because, the atomic mass does not tell anything about the availability or natural abundance of an element.
Now, the isotopes of an element are those elements, which have same number of electrons and protons as the original element, but different number of neutrons. Therefore, they have same atomic number but, different atomic weight or atomic masses.
Hence, by looking at an elements having same atomic number, but different atomic masses, we can identify them as isotopes.
Thus, the correct option is:
<u>A. there is an isotope of lanthanum with an atomic mass of 138.9.</u>
Combustion Have a great day!
Answer:
The answer is "
"
Explanation:
Given:
Molarity= number of moles
because it is 1 Liter
therefore,
it takes 20 mL of Tris.
So, take 
The answer is B because isotopes have the same number of protons and neutrons.
Answer:
The left and right hemispheres of the cerebrum are connected by the Corpus Collosum.
Explanation:
The corpus collosum is a thick band of neurons that divides the cerebral cortex lobes into the left and right hemisphere. The corpus callosum allows for both hemispheres to communicate and transfer information! The primary function of the corpus callosum is to integrate sensory, motor, and cognitive performance between the cerebral cortex.
Ins severe cases of epileptic seizures, a corpus callosotomy is performed, which cuts the corpus callosum in half. This prevents the seizures from becoming more severe, and the brain can reprogram, through neuroplasticity.
