Answer:
most effective way to combine sentences 10 and 11 is Eventually, the Romans used the umbrella to protect themselves from the rain as well as the sun.
When combining two sentences, the sentences are always independent clauses. In other words, a compound sentence contains two units of thought in a sentence. These are connected by coordinating conjunctions or separated by a comma.
Hence, the above sentence which combines sentences 10 and 11, uses coordinating conjunction 'as well as' which helps in connecting two units in a sentence.
Read the passage. (1) The umbrella dates back more than 3,000 years to Mesopotamia. (2) That ancient land was located in the Middle East. (3) The Middle East is a hot and sunny part of the world. (4) Royalty there demanded protection from the sun. (5) People developed the umbrella for this purpose. (6) Use of the umbrella as a sunshade then spread to ancient Europe. (7) In fact, if you analyze the origin of the word umbrella, you will see that it reflects the umbrella’s original purpose. (8) Umbrella comes from the Latin word umbra. (9) Umbra means “shade.” (10) Eventually, the Romans used the umbrella to protect themselves from the rain. (11) They used the umbrella to protect themselves from the sun as well. (12) Today, umbrellas are used mainly as raingear. Which is the most effective way to combine sentences 10 and 11? Eventually, the Romans used the umbrella to protect themselves from the rain as well as the sun. Eventually, the Romans using the umbrella to rotect themselves from the rain as well as the sun. Eventually, the Romans used for protection from the rain as well as the sun, the umbrella. Eventually using the umbrella as protection from the rain as well as the sun, the Romans.