Question

QUESTION 26

Certain types of atoms break down at a known rate. Scientists can measure the amounts of the broken down products present in a sample to calculate its age. What is this technique called?

natural selection

the fossil record

speciation

radiometric dating
2 points
QUESTION 27

During which era did plants first appear on land?

Cenozoic

Mesozoic

Paleozoic

Precambrian
2 points
QUESTION 28

How were multicellular organisms developed on early Earth?

eukaryotes began grouping together to develop multicellular organisms

cyanobacteria released oxygen molecules into the air creating new multicellular organisms

prokaryotes combined to form new multicellular organisms

prokaryotes combined with cyanobacteria to develop multicellular organisms

Answer 1

QUESTION 26

Answer: D.)
Radiometric dating is the right answer

QUESTION 27

Answer: C.)
Paleozoic Era; The Paleozoic Era began with the Cambrian Explosion, a relatively rapid period of speciation that kicked off a long period of life flourishing on Earth. Great amounts of life from the oceans moved onto the land. Plants made the move first, followed by invertebrates. Not long afterward, vertebrates took to the land. Many new species appeared and thrived.

QUESTION 28

I believe the answer is C.)
But it may be D.)

Prokaryotes combined to form new multicellular organisms.

The answer to this question is usually cooperation, as cells benefitted more from working together than they would from living alone.