Answer:
The answer is autotrophs
Explanation:
During the early days of the Earths life there was no oxygen but there was plenty of CO2 which the autotrophs took and used as food while discarding the excess which was the oxygen.
<span>A. The nebula contracts and shrinks instead of expanding
</span><span>Nebula is the cloud of interstellar dust and gas that forms a star. It is collborately shaped during colliding and collapsing of the interstellar mediums this is influenced by the gravitational attraction of the atoms and particles in the entites. Hence, there are three types of nebular namely, are classical nebula, diffuse nebula, planetary nebular and supernova remnants.</span>
<span>the passing of fatal diseases from one organism to another hope this helps</span>
Answer:
d. Smoking
Explanation:
Nicotine is a chemical found in many plants such as tobacco. It is one of the 4000 chemicals that tobacco presents and the main component that acts in the brain.
This chemical is absorbed through the skin and lining of the mucosa of the nose and mouth, or in the lungs by prior inhalation. Nicotine can quickly reach the bloodstream and brain and reach maximum levels. The action of smoking cigarettes causes nicotine to reach the brain in just 10 seconds after inhalation. Although the acute effects dissipate in a few minutes, they cause the need to continue the intake of the substance (addiction)
