In the race to the moon，who came in first?
You might say the answer is Neil Armstrong，Buzz Aldrin，and
Michael Collins，the crew of Apollo 11.Or you could represent for the
crew of Apollo 10，which reached the moon in May1969 and then headed back to Earth without landing.
But there is a much stranger answer to this question，depending on
how much you care about humans and what your definition（定义）of
reaching the moon might be.Before any people arrived at the moon，
other animals had got there first.And unlike the dogs and monkeys that
were made famous in early space shots and Earth orbits，the first
creatures to reach the moon were a pair of tortoises，Discovery's Amy
Shira Teitel reminded us.
The Soviet spacecraft（航天器）sent the animals around the moon—although not into its orbit—during a mission in the middle of September，1968.The unmanned（无人驾驶的）craft then returned to Earth and dashed into the Indian Ocean，after which the Russians recovered the craft.
A month later，Soviet scientists revealed that the spacecraft had been a tiny ship，carrying the tortoises，wine flies，meal worms，plants，
seeds，bacteria，and other living matter.
The tortoises，as history records，lost about 10 percent of their body weight，but had a healthy appetite when they returned to Earth.In the following checkups comparing the animals to stay-at-home turtles used as a test control，"most things seemed normal，aside from some vaguely explained minor problems with the liver.
What this all means is that，as Teitel explained，"The first living beings to see an Earthrise from the Moon were Russian tortoises.However，as far as I can tell，the animals were not named.”
What was the biggest change in the tortoises in Paragraph 6?
文章第六段提到，据史料记载，这些乌龟的体重下降了约10%，但回到地球后却有健康的食欲。在接下来的检查中，将这些动物与“作为试验对照的留守龟”进行比较，除了一些解释不清的肝脏小问题外，大多数事情似乎都很正常。故选D。
