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

• The phrase “more achievement oriented” in the paragraph 6 is closest in meaning to ______.

• What is the main idea of the passage?

• According to the passage, red algae is________.

ZUNIA12

• The passage supports which of the following conclusions?

• During the procedure described in paragraph 3, when clay particles are placed into water they ______.

• According to the passage, ..................

• What can we assume is NOT true about Middle Earth?

• The word “urgent” in the last paragraph probably means .............

• According to the passage, the first refrigerated railcar used what material as a cooling agent?

• The word “checked” in the second paragraph is closest in meaning to ______.

• The word “enclaves” is closest in meaning to .........

• How would the author probably characterize the people who are mentioned in the first line of the second paragraph?

• Merlin put wheels under his shoes in order to ..................

• The word “hurdles” can be best replaced by ___________.

• According to the second paragraph, a useful theory is one that helps scientists to _______.

• What can be said about the mother and son in the passage?

• According to the passage, which of the following is true?

• By discovering and better understanding your own learning styles, you can improve ..............

• Which of the following is NOT mentioned as the denomination of an American coin?

• According to the passage, which of the following countries attracts more tourists than the others?