What is the difference between food web and food chain and what do they have in common?

A food web is a system of interlocking and interdependent food chains.

A food chain is a hierarchical series of organisms each dependent on the next as a source of food.

Basically, the difference of the two is that a food web contains multiple different species in the same level that eat the animal below it's status. A food chain is one after the other.

the answer to your question is c.

if you read the house of usher you should know that the house was haunted

explanation:

venn diagram is pictorial representation with of circles showing the relation between two finite sets or things. the intersection part of two circles conveys the relation present in between those sets or things.

here in the venn diagram of sand and salt two circles represent sand and salt. but the area falling under the intersection of these circle represents the mixture of sand and salt.

so, in a venn diagram the mixture will be placed in a middle that is in between the intersection of two circles.