Dquestion 10 0.34 pts how long does a vertebrate species tend to appear in the fossil record? 10 billion years o 1 billion years o 10 years 1 million years 100 million years d question 11 0.33 pts why does the discovery of an iridium-rich layer at the end of the an asteroid strike was likely the cause of the cretaceous extinction? cretaceous show that iridium is common in the banded iron formations iridium iis very radioactive, with a half-life of 1 day asteroids are rich in iridium, but the crust of the earth is not ridium is an organism that forms in impacts volcanoes spew a lot of iridium when they erupt d | question 12 0.33 pts which of the following is evidence that land animals evolved from aquatic organisms? embryos of land animals develop in a wet environment all of the other answers are correct fertilization in animals always happens in a wet environment concentration of salt in seawater is the same as the concentration in blood proportions of potassium, sodium, and chloride in animal tissues is similer to the in the ocean

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

it's c (engineer's do their work with mechanical stuff not on any living being)

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l