DNA? I think I'm not 100% sure
<h2><u>Answer:</u></h2>
The correct option is B (The longer-spined sea urchins existed before the shorter-spined sea urchins.)
<h3><u>Explanation:</u></h3>
The more drawn out spined ocean urchins existed before the shorter-spined ocean urchins.
Since the shorter spined urchins are higher up, that demonstrates that they developed from the more drawn out spined urchins, implying that having the shorter spines was useful to them as an animal types, so the shorter spines came AFTER the more extended spines.
Answer:
Hey there.
<em><u>There are three types of scientific investigations: descriptive, comparative, and experimental scenitific investigations.
</u></em>
<em><u></u></em>
fist we have <em><u>Descriptive</u></em> scientific investigations.
Descriptive investigations use careful observations and measurements to develop findings.
Then we have <em><u>
comparative </u></em>Investigation.
comparative investigations Involve collecting data on different populations/organisms, under different conditions (Times of year, locations), to make a comparison. for Example, Using a hand lens to examine the color and texture of four different rocks.
Lastly we have <em><u>experimental</u></em> scientific investigations.
Experimental investigations involve a process in which a "fair test" is designed and variables are actively manipulated, controlled,
I hope it helped!!!
<em>Wbob1314</em>
The period during which the presence of stromatolites decline is the Proterzoic period. Stromatolites are widely distributed sedimentary structures consisting of laminated carbonate or silicate rocks, produced over geologic time by the trapping, binding, or the precipitating of sediment by groups of microorganisms, primarily cyanobacteria.
