The correct answer to this question is this one: they lacked oxygen. The earliest organisms were completely heterotrophic in nature because of the reason that they lacked oxygen. <span>A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. </span>
Ancient organism remains, fossil layers, similarities among organisms alive today, similarities in DNA and similarities of embryos.
Answer:
oxygen and glucose
your welcome i hope this helps
Explanation:
The data you will collect is the blood phenotype.By adding serums that each contains a particular antibody such as anti-A, anti-B, or anti-D ... to see if there's an agglutination with erythrocytes' antigen and the antibodies, proving the presence of the appropriate antigen in the blood.
This will help to confirm the blood grouping if this technique is done in parallel with the plasma test ( of Simonin-Michon).
All galaxies have a dense core of stars. Spiral galaxies, however, have arms that are often visible. There are two kinds of spiral galaxies: barred, where there appears to be a line running from arm to arm through the core, and <span>ordinary, where there is no bar. @Badbunnyhunny</span>
