Create an ERD based on the Crow's Foot notation using the following requirements:

1. An INVOICE is written by a SALESREP. Each sales representative can write many invoices, but each invoice is written by a single sales representative.
2. The INVOICE is written for a single CUSTOMER. However, each customer can have many invoices.
3. An INVOICE can include many detail lines (LINE), each of which describes one product bought by the customer.
4. The product information is stored in a PRODUCT entity. The product's vendor information is found in a VENDOR entity.

if you go to ask a question say ask, there should be something that looks like this. a camera lens.

the major difference between the two is the objective and the reward of the game. candy crush has a puzzle theme with the objective of meeting a specific quota of points or objects, you are able to gain access to the next level and compete with peers on the process. on duolingo the objective is rather different, you are given sets of questions for you to answer for you to move to the next level and as for the reward, you are able to learn available language as this is an app developed to teach the user about other languages.