Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high- intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface.

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

Green algae is generally found .............

Câu hỏi liên quan

• According to the passage, an overconfident front may hide _______.

• Which of the following is a kind of petal?

• The word “fledgling” in the third paragraph could be best replaced by which of the following?

ZUNIA12

• According to the writer, why is the choice of your second job important?

• Green algae is generally found________.

• The word “bounds” in line 5 is closest in meaning to ......

• The word "derived" in line 13 is closest in meaning to ____________.

• Which of the following terms does the author define in the first paragraph?

• The word cherished in paragraph 1 is closest in meaning to _______________

• We can see from the passage that in the countryside of Britain ______.

• According to the passage, what group of people will probably first from the use of the microprocessor?

• What is the best title for the passage?

• According to the passage the first fire used by people was probably obtained ..........

• According to the passage, which of the following is NOT true?

• Which of the following has nothing to do with the isolation among Americans?

• The word “reluctant” in the third paragraph can best be replaced by ............

• Why were the telephone, radio, and television invented?

• According to paragraph 4, which of the following is the most fascinating to booklovers?

• Which of the following is TRUE according to the passage?

• After which year did the town really begin developing?