Excerpt from Atomic Theory Clark Benson:
Early twenty-first century technology has given today's scientists the opportunity to
conduct even more complex experiments with atoms. Scientists now use massive
machines called particle accelerators, or "atom smashers." Particle accelerators are capable
of taking subatomic particles, such as an electron, and speeding them up to near the speed
of light. Once the particle has reached the proper speed, it is sent on a collision course
with another particle or atom. The impact breaks up the electron and reveals its inner
parts, giving researchers a glimpse into what makes up the particle. Physicists hope that
continued advances in technology and research will answer one of humankind's most basic
yet important questions: What are we all made of?
Which subject is discussed in paragraph 6?

A)the discovery of neutrons
B)how atoms are put together
C)the person who discovered atoms
D)how subatomic particles are used

explanation:

kim antonie lode clijsters[1] (dutch pronunciation: [kɪm ˈklɛistərs] (about this soundlisten); born 8 june 1983) is a belgian former professional tennis player. clijsters was a world no. 1 in both singles and doubles, having held both rankings simultaneously in 2003. she won a total of six grand slam tournament titles, four in singles and two in doubles.

clijsters competed professionally from 1997 to 2012 in an era where her primary rivals were compatriot justine henin and 23-time grand slam singles champion serena williams. coming from a country with limited success in men's or women's tennis, clijsters became the first belgian player to attain the no. 1 ranking. together with henin, she established belgium as a leading force in women's tennis as the two of them led their country to their first fed cup crown in 2001 and were the top two players in the world in late 2003. individually, clijsters won 41 singles titles and 11 doubles titles on the women's tennis association (wta) tour. she was a three-time winner of the wta tour championships. between singles and doubles, she was a champion at all four grand slam tournaments, winning the us open and the australian open in singles and wimbledon and the french open in doubles with ai sugiyama. her success at majors was highlighted by winning three consecutive appearances at the us open.

plagued by injuries and having lost some of her desire to compete, clijsters initially retired from tennis in 2007 at the age of 23 to get married and have a daughter. she returned to the sport two years later and won her second us open title as an unranked player in just her third tournament back. she defended her title the following year and then won the australian open in 2011 en route to becoming the first mother to be ranked no. 1 by the wta. along with margaret court, she also holds the record for most grand slam singles titles won as a mother with three and was the first to win one since evonne goolagong cawley in 1980. she officially retired from professional tennis after the 2012 us open.

clijsters was born to athletic parents with backgrounds in professional football and gymnastics. she was renowned for her athleticism, which was highlighted by her ability to perform splits on court in the middle of points. she built the offensive side of her game around controlled aggression while also using her exceptional movement to become an elite defensive player. clijsters was very popular and well-liked as a player, having won the karen krantzcke sportsmanship award eight times. she was inducted into the international tennis hall of fame in 2017.

contents

1 early life and background

2 junior career

3 professional career

3.1 1997–99: maiden wta title, newcomer of the year

3.2 2000–02: french open finalist, tour champion

3.3 2003: world no. 1 in singles and doubles

3.3.1 singles: two grand slam finals, tour championship defense

3.3.2 doubles: french open and wimbledon titles

3.4 2004–05: extended injury absence, first grand slam singles title

3.5 2006–07: return to no. 1, hastened retirement

3.6 two-year hiatus

3.7 2009–10: start of second career, back-to-back us open titles

3.8 2011–12: australian open champion, last reign at no. 1

4 national representation

4.1 fed cup

4.2 hopman cup

4.3 olympics

5 rivalries

5.1 clijsters vs. henin

5.2 clijsters vs. williams sisters

5.3 other rivals

6 exhibition matches

7 legacy

8 playing style

9 coaches

10 endorsements

11 personal life

12 career statistics

12.1 performance timelines

12.1.1 singles

12.1.2 doubles

12.2 grand slam tournament finals

12.2.1 singles: 8 (4 titles, 4 runner-ups)

12.2.2 doubles: 3 (2 titles, 1 runner-up)

12.2.3 mixed doubles: 1 (1 runner-up)

13 awards

14 see also

15 references

15.1 books

16 external links

his research revealed two genetically different groups of prokaryotes, which justified splitting kingdom monera into two kingdoms. the genetic and cellular differences were so great, that these two kingdoms were eventually placed into different domains in the current three-domain system.

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.