Answer: The cell is eukaryotic because it has chloroplasts. A scientist is studying a cell and can clearly see that it has ribosomes and mitochondria.
Explanation:
Work is done on an object only if the force and displacement are in the same direction.
Answer:
In the food chain, producer makes the base, primary and secondary consumers are present in the middle and tertiary consumers is present on the top.
Explanation:
Producers are the organisms which makes their own food such as plants. They are placed at the base due to high population. Primary and secondary consumers are placed in the middle due to less population than producer and tertiary consumers are placed on the top due to very low population.
I believe that what is meant with the phrase "older explanation" is none other that superstition. Therefore, I will give you one superstitious belief which is now explained by science.
In Southeast Asia, people used to believe that St. Elmo's fire appears in remote areas because a bloody battle occured in that place leaving disembodied souls of the dead wandering there in the night and even in sunshine!
For generations, many people believed that this is a fact and some even say that these apparitions are diabolical or demonic in nature. So often, caution is advised to people whenever a ball of fire appears out in the open.
However, recent breakthroughs in the 21st century helped scientists to explain this mysterious phenomena. They found out that St. Elmo's fire is actually plasma, nothing special. Now, plasma is considered one of the states of matter! But mind you, it still does not explain why St. Elmo's fire seems to have a mind of its own!
