I'm pretty sure this is A
Hi,
The correct answer is letter B.
The last group contains noble gases, while both along the top and along the bottom the elements on the right are non-metals.
The answer is C. Neutron star.
Caves are formed by the dissolution of limestone. Rainwater picks up carbon dioxide from the air and as it percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone along the joints, bedding planes and fractures, some of which become enlarged enough to form caves
