biology question help

<p>On my Bio test that I took today one of the questions was:
The first cells on earth were probably:
A. Colonial Volvox
B. Eukaryotes
C. Prokaryotes that did not make their own food
D. Prokaryotes that made their own food.</p>

<p>The answer I put was C. but D. looked good too...can anyone confirm my answer?</p>

<p>C looks right to me. If I remember correctly, the first cells got their energy from breaking down organic molecules.</p>

<p>I'm 99% positive it's C. And that's only because I like to leave 1% margin for error.</p>

<p>c looks right</p>

<p>It's C because there was virtually no oxygen during this time. They're Heterotrophs.</p>

<p>Ok. Thanks guys for your replies!</p>

<p>i hated biology. i loveee chemistry :]</p>

<p>Bad question- can be either C or D</p>

<p>Short answer: we don't know. The most primitive bacteria today, archaebacteria, use chemosynthesis as a source of energy. In order to do this, a cell requires a fairly complex membrane that can maintain a proton gradient. The alternate scenerio is heterotrophy, but the capturing of organic molecules would also necessitate a cell membrane. Scientists do know that photosynthesis came along slightly later (usually thought to be introduced by cyanobacteria).</p>