How does filtration occur during the formation of urine? a. gravity forces large particles to filter through capillary walls of the glomerulus. b. bowman's capsules collect dissolved substances and transfer them to the peritubular capillaries, c. pressure causes water and dissolved substances to filter through capillary walls of the glomerulus d. nephron tubes filter waste products and transfer them into the collecting tubules, reset next

a = executive branch; b = judicial branch

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.