Read the following passage. Multiple questions may be based on this passage. The passage will be displayed for every question. Scroll down to see the question / correct answer.

(1) The world is full of all types of trees, but one type of tree regularly grows over 300 feet tall. It is the coastal redwood tree, officially named Sequoia sempervirens. The tallest tree standing in theUnited States is a redwood. It is 374 feet tall — as tall as a 30-story building. Oak, maple, and elm trees rarely tower more than one hundred feet. A redwood is more than three times that height. The girth of the redwood tree, which is the measurement of the trunk size, is also significant and can be up to 18 feet in diameter.

(2) The coastal redwood tree grows in a 450-mile strip on the coast along the Pacific Ocean from southern Oregon to just south of San Francisco, California. This area is a moist, fog-covered canyon that supports these huge trees. The redwood species thrives on moisture and cannot survive more than 30 to 40 miles away from the coast. The canyon creeks that flow through the redwood forests provide moisture, but they dry up in the summer. The constant fog in the area lowers the temperature, provides humidity, and creates moisture for these trees by condensing and settling on the needles, then dripping to the ground. Evidence has shown that fog drip creates up to 10 inches of moisture annually for the redwood trees. The forest floor that surrounds the redwoods is filled with dropped needles, trapped dust, seeds, and other natural materials forming a mat of mulch. This mat traps moisture for the trees to use during the dry summers.

(3) Redwoods grow swiftly and survive hundreds of years. Some redwoods even live longer than two thousand years. Their heights and their ages make them unusual and unique among tree species. Scientists say that the oldest living redwood tree is about 2,200 years old. Redwoods have characteristics that make them healthy and strong in their environment. Their bark is fire resistant, from 6 to 12 inches thick, and does not contain the sticky resins that can fuel a fire. Redwoods are resistant to disease and undesirable to insects that consume wood.

(4) Redwood trees have shallow roots that rest near the top of the soil, which seems unusual for their size. Their main roots, known as the taproots, do not burrow deeply into the ground like so many other trees. Redwoods form a wide radius of shallow roots around their base, and this is what has helped them survive for so many years. These trees are able to survive flooding and the resulting mudflows that cover the roots because they grow new roots quickly. The old roots simply rot away from being buried so deeply.

(5) In the redwood forests of California, the redwood trees are the dominant living plants. The canopy of shade that these giant trees provide makes it extremely difficult for many other plants to grow alongside them. A variety of events are organized by the Redwood National and State Parks in California, so the whole family can enjoy the awe of the tallest trees in the world. Even though the redwoods have a thick bark that is resistant to fire, repeated fires occasionally damage them. They bear the black marks of fire damage and begin decaying. A process called stump sprouting then occurs. The decaying tree sends out root buds that begin growing around it. Small saplings, or beginner trees, start to grow and survive. In the forest, there are often many saplings surrounding a fire-damaged redwood because they are the only plants that survive in the shady, moist environment.

(6) The stump-sprouting process of redwood tree reproduction is much more successful than seeding. All redwoods have cones growing within their branches. The cones release tiny brown seeds when the tree is mature. The brown seeds are so tiny that thousands are needed to create a pound. Individual trees produce up to 6 million seeds annually! Yet, a scant 5 percent of these seeds actually germinate and even less actually grow into mature trees. The already established root systems from the stump-sprouted trees provide the new saplings with the ability to grow more forcefully than the seeded trees.

(7) The redwood tree is the California state tree. It is magnificent in size, stature, and longevity. Visitors come from all over the world to see the redwoods and to enjoy their greatness.

(1) Read the sentence below in paragraph 5:
"In the redwood forests of California, the redwood trees are the dominant living plants."

What is the meaning of the word: "dominant"?