Cross over? i have no idea lol
Answer:
Q2->They all form acids when combined with hydrogen. They are all fairly toxic. They readily combine with metals to form salts.
Q3->Because their outermost orbit is complete. In Mendeleev's original periodic table there was no place reserved for noble gas. They were discovered in end of 19th century. So Mendeleev created zero group without disturbing original periodic table.
Explanation:
Starfish have a unique form of digestion in the animal kingdom and a water-vascular system that allows the animal to breathe.
All your answers should be in this article:
http://animals.mom.me/feeding-respiration-starfish-6596.html
