<span> They contain their own DNA in the form of a circular plasmid which encodes some - but not all - of the molecules needed for chloroplast function.. It is theorized that this is the DNA from the free-living photosynthetic prokaryote that became an endosymbiont and then an organelle. This theory, The Endosymbiotic Theory, is widely accepted as a plausible explanation for the evolution of organelles. </span>
The nucleus directs the cell activities and reproduction.
The answer should be photosphere zone.
Answer:
Yes.
Explanation:
Yes, Schwann and Schleiden are responsible for the cell theory, both the scientists presented the cell theory in 1839. I agree with the argument of my classmate because the person who first presented cell theory was both Schwann and Schleiden. Schwann works on plant cell whereas Schleiden works on animal cell and formulate cell theory. So my classmate's argument is right about cell theory.
Answer:
The human heart has it own nervous system, nodal system. It's made of nodes (that produces nerve impulses) and nerve fibers (running to all parts of the heart). Our nervous system can only increase or decreasing the nodes firing rates.
Starting with deoxygenated blood (oxygen poor blood), it travels from the superior and inferior vena cava into the right atrium, then into the right ventricle via the tricuspid value. There, it enters the pulmonary arteries via the pulmonic value. From there, it heads to the lungs and become oxygenated (rich in oxygen). It re-enters the left atrium of the heart via the pulmonary veins. There, it now travels to the left ventricle via the mitral valve and then into the aorta via the aortic value. From there it travels to the rest of the body supplying cells with oxygen and return back via the vena cava.
