Answer:
answer is b
Explanation:
All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor
Answer:
The Sun and the planets were born from a cloud of gas and dust called the solar nebula 4.6 billion years ago. The collapse of the solar nebula was most likely triggered by a shock wave from a nearby supernova explosion. The Sun formed in the center, with the planets surrounding it in a thin disk.
Explanation:
