2. From about 4 billion years ago to about 2.5 billion years ago, oxygen gas 2 points became more common in Earth's atmosphere. Oxygen was a toxic
compound to most life forms from that time period. Today, oxygen is
required by all but some of the most primitive life forms. Which statement
best explains how early life forms that were harmed by oxygen evolved
into today's life forms that require it?
A Warming temperatures allowed the colonization of land environments, where
oxygen was more plentiful
B. Over time, many species gradually adapted to a more oxygen-rich environment,
allowing them to survive in shallow water and on land
C. Carbon dioxide-using species all became extinct, which allowed oxygenusing life
forms to flourish in shallow oceans.
D The growth of seas allowed early species to survive by using dissolved carbon
dioxide in seawater rather than using it directly from the air
3. Which sequence of events best describes the current theory of the
origin of life on Earth?

hydroxyl -oh

alcohols, always polar, can form hydrogen bonds with h2o molecules

carboxyl -cooh  

cargoxylic acids, has acidic properties which is a source of hydrogen ions, found in cells in ionized for with a charge of oh-1

carbonyl > co

ketone if within skeleton, aldehyde if group is at the end of skeleton, k & a may be structural isomers, it determines 2 sugars (ketose & aldose)

amino -nh2

amines, acts as a base, it can pick up h+ ions from surrounding solution, ionized with charge of 1+

methyl ch2

addition to rna/dna affects and gene expression

phosphate -opo3 ²⁻

organic phosphates, contributes to negative charge to, molecule that it is a part of, and potential to react with h20

sulfhydryl -sh

thiols, cross-linking stabilize the protein, and it is structure

a

explanation:

many plants naturally reproduce this way, but it can also be induced artificially. horticulturalists have developed asexual propagation techniques that use vegetative plant parts to replicate plants. success rates and difficulty of propagation vary greatly. monocotyledons typically lack a vascular cambium and therefore are harder to propagate.

not too sure but maybe in the hot springs.