Answer:The answer is tiny organisms known as cyanobacteria, or blue-green algae.
Explanation:
These microbes conduct photosynthesis: using sunshine, water and carbon dioxide to produce carbohydrates and oxygen increase. Additionally, some sources you could use that I used to answer this question was
https://www.scientificamerican.com/article/origin-of-oxygen-in-atmosphere/
<span>Features matched with its description
A: stalactites 3: tubes with hollow centers
B: stalagmites 2: tubes without hollow centers</span>
<span>C: speleology 1: cave science</span>
D: speleothems 4: cave features
<span>
</span>Speleology is shortly defined as the<span> scientific study of caves.</span> Speleothems are structures<span> formed in a cave by the deposits of minerals from water dripping from the fractures of the ceiling of the cave. Most common types are the stalactites and stalagmites. </span>
<span>Stalactites began as a ring of crystals which later becomes small tubes with a hollow center.</span><span> Stalagmites, on the other hand, are tubes formed without hollow centers. </span>
The four postulates of the natural selection include.
1. individuals possessing particular traits are have higher likelihood of surviving and reproducing.
2. different individuals in a population have different traits
3.reproductive and survival rate vary with individuals in a given population.
4. some trait differences are inheritable.
Alfred Wegener found some evidence and these are some examples:The Appalachian Mountains start in North America and it is connected along the European coastline. This tells us that once the continents were connected,and,The continents fit together like a puzzle.Also some of the fossils are found around the borderlines
hope this helps man and could i please get brainliest
:D
