Answer:
element
Explanation:
we know that helium is a pure substance although helium atoms are sometimes mixed with their isotopes it is still the same element. since there is no other element combined with helium this makes it an element.
I think it’s D. Stars and planets.
Answer
A. None of these
Explanation
Gamma rays are ionizing electromagnetic radiation, obtained by the decay of an atomic nucleus. Gamma rays are more penetrating, in the matter, and can damage living cells to a great extent. Gamma rays are used in medicine (radiotherapy), industry (sterilization and disinfection), and the nuclear industry.
Thus, gamma rays are used for all the options given in B - D. So the correct answer is option A. None of these
<span>1. Ionic bonding involves the ________ of electrons, whereas covalent bonding involves the _______ of electrons.
A. transfer, sharing
2.
Which scientist found that gas expands to fill the space of a container and is made of particles that can move?
B. Boyle
3. When acids contact metal, they are ______.
B. corrosive
4. Different types of matter melt at different temperatures.
True
</span>
Seen in the electrons, which are found in the atomic cloud surrounding the nucleus.
