Chemistry, 19.08.2019 06:20 marifermolina

According to scientific evidence, earth’s earliest atmosphere lacked oxygen. over time, oxygen was added to the atmosphere.
which statements explain how this change occurred and how it affected life on earth?
choose all answers that are correct.
a.
the addition of oxygen to the earth's atmosphere make possible the development of eukaryotic organisms, which need oxygen to carry out many of their life processes.
b.
when cyanobacteria evolved, they carried out photosynthesis. oxygen is a product of photosynthesis. the addition of oxygen to earth’s atmosphere make possible the development of eukaryotic organisms, which need oxygen to carry out many of their life processes.
c.
the addition of oxygen to the earth's atmosphere make possible the development of prokaryotic organisms, which need oxygen to carry out many of their life processes.
d.
when cyanobacteria evolved, they carried out photosynthesis. oxygen is needed to carry out photosynthesis.

Answers: 1

Show answers

Another question on Chemistry

Chemistry, 22.06.2019 07:30

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н,о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

Answers: 2

Answer

Chemistry, 22.06.2019 21:50

Liquid from a brewery fermentation contains 10% ethanol and 90% water. part of the fermentation product (50,000 kg/h) is pumped to a distillation column on the factory site. under current operating conditions, a distillate of 45% ethanol and 55% water is produced from the top of the column at a rate of one-tenth that of the feed. what is the composition of the waste "bottoms" from the still?

Answers: 2

Answer

Chemistry, 23.06.2019 06:00

If you try to move a piano and are unable to move it, did you perform any work in the scientific sense of the word? yes? or no? this question is worth 20 points! let it be correct!

Answers: 1

Answer

Chemistry, 23.06.2019 06:40

A250 g sample of water with an initial temperatureof 98.8 closes 6500 joules of heat. what is the finaltemperature of the water?

Answers: 1

Answer

You know the right answer?

According to scientific evidence, earth’s earliest atmosphere lacked oxygen. over time, oxygen was a...

Questions