The answer is b. radon-222. The alpha decay means that it will emit an alpha particle when decays. The alpha particle has two protons and two neutrons. So Radium(88) minus two protons will become Radon(86). And the atomic mass will become 226-4=222.
Answer:
First and last sentence .♀️
Explanation:
An important thing to keep in mind about the Reading Comprehension section of the GRE as we use PowerPrep online to study is that it is just that—reading comprehension. In other words, as difficult as it may seem, and it can be pretty tricky, the test makers will always give us all the information we need in the passage to answer the question.
A. A group of related objects that do not send out or receive feedback and cannot modify themselves
Explanation:
An open-loop system is a a group of related objects or systems that cannot send out or receive feedback and modify themselves.
- It is a non-feedback system.
- In this system, the output control system has no effect on whatever input that is fed into the system.
- Output and input in such systems are independent of one another.
- The input and output has no control whatever on each other.
learn more:
Computer programs brainly.com/question/9409412
#learnwithBrainly
<span>The symbol for the element whose atoms have 40 electrons each is Zr. This is the element zirconium. In the atoms of a pure element, the number of positively charged protons is normally equal to the number of negatively charged electrons. Hence, the number of electrons in the atom can be inferred from the atomic number, which corresponds to the number of protons in an atom. The atomic number of zirconium is 40.</span>
Soil
profile
Soil
profile is the vertical sequence of the layers of soil. Furthermore, there are
actually six layers of the soil which involves the organic matter, -where most
humus is present-, surface soil, the subsoil, the parent rock, and the bedrock
as the innermost and core layer of the soil. In addition each soil layer has
three to four soil horizon. These horizons are the physical features of the soil,
mainly the texture, color and composition.