Four differences between Arteries and Veins

Veins

1l carry blood from tissue of the body to the heart

2) are usually found closer beneath the skin

3) are less muscular then arteries

4) collapse if blood flow stops

arteries

1) carry blood back away from the heart to the tissue of the body.

2) found deeper within the body

3) are more muscular then veins

4) would generally remain open even if blood stops because of it's muscular structure.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

the alkaline earth metals (beryllium (be), magnesium (mg), calcium (ca), strontium (sr), barium (ba), and radium (ra)) are a group of chemical elements in the s-block of the periodic table with very similar properties: shiny. silvery-white. hopefully this ? i didn't fully understand the question