题目内容：

From babies to body builders, we all have muscles. They grow, they bulge(鼓起), they stretch they stretch and sometimes they even painfully pull. But for all the work they do for us, we are still unable to crown one as "the strongest muscle."

Instead, a few muscles could claim the title, depending on how strength is measured.

If the title goes to the muscle that can exert(产生) the most force, the victor would be the soleus（小腿肚肌）, according to Gray's Anatomy（解剖学）. Without this muscle, we wouldn't be able to stand, walk, run or shake our bodies on the dance floor. If the soleus was not continuously pulling, we would always be falling over ourselves (although some of us tend to do that from time to time anyway).

But perhaps the title should go to the muscle that exerts the most pressure. Pressure is different from force — pressure takes into account the area over which a force is exerted. The muscle that takes the prize for delivering the greatest amount of pressure is the masseter, or the jaw muscle, according to the book "Clinical Oral Science" (Reed Educational and Professional Publishing, 1998).

In 1986, Richard Hofmann of Lake City, Fla., achieved a bite strength of 975 pounds (442 kilograms) for two seconds, setting a Guinness Record. Talk about jaw dropping! The jaw is able to clench（咬紧） and chew because of the masseter muscle.

Others may argue the muscles used in childbirth are the most powerful.

When it comes to versatility, perhaps the tongue is the strongest muscle. Its combination of elasticity（伸缩性） and forcefulness gives us the ability to speak, eat and kiss – all things very desirable on a first date. However dexterous（灵巧的） it may be though, its power does not match that of muscles such as the soleus.

If slow and steady wins the race, the heart is certainly a contender for the title. When it contracts, the muscle pumps about 2 ounces (59 milliliters) of blood, and is constantly working over a lifetime. Beating about 40 million times a year, a person's heart will beat approximately 2.5 billion times by the time of their 70th birthday.

1.According the passage, the underlined word “contender” in the last paragraph is closet in meaning to “          ”.

A．failure

B．partner

C．muscle

D．competitor

2.Which would be t he best title for the passage?

A．What’s the strongest muscle in the human body?

B．who is the strongest person in the world?

C．What are the functions of different muscles?

D．What are the standards of the strongest muscle?

3.According to the passage,       .

A．Without the soleus, we could still stand, walk, run or shake our bodies on the dance floor

B．a few muscles could be the winners, according to different measures

C．the muscles used in childbirth are the most powerful

D．tongue is the strongest muscle for delivering the greatest amount of pressure

4.What would be discussed in the following paragraph?

A．Another possible strongest muscle.	B．the conclusion of the strongest muscle.
C．The functions of different muscles.	D．the Guinness record of strongest muscle.