Which concept is described in the theory proposed by Hess?

Continents do not move.
Cool rock pushes through the crust.
Trenches are sites of seafloor spreading.
Mid-ocean ridges are sites of seafloor spreading.

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.

the correct answer is anaphylaxis.

anaphylaxis is a condition caused by insect bites, foods, medications, manifested by tongue swelling, shortness of breath, vomiting, low blood pressure. it sometimes may occur without an obvious reason. it is treated with epinephrine injection.other tretments include antihistamines and steroids,