What does “they” refer to? 

Algae is a primitive form of life, a single-celled or simple multiplecelled 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. 

What is the author's main purpose?

Which of the following is NOT true about algae?

The word “gloomy” in the passage is closest in meaning to .............

The Hindu culture celebrates marriage as a pure and pristine rite enabling two individuals start their journey of life together. It puts emphasis on the values of happiness, harmony and growth and could be traced back from the Vedic times. Months before the wedding ceremony, an engagement is held which is called “magni”. The couple is blessed here with gifts, jewelry and clothes. Another important ritual is the “mehendi” which is a paste made from the leaves of henna plant. It is the traditional art of adorning the hands and the feet of the bride with mehendi and the name of the groom is also hidden in the design. On the day of marriage, the couple exchanges garlands as a gesture of acceptance of one another and a pledge to respect one another as partners which is known as «jaimala». This is followed by «jaimala», where the father of the bride places her hand in the groom’s hand requesting him to accept her as an equal partner. Another ritual is the «havan» in which the couple invokes Agni, the god of Fire, to witness their commitment to each other. Crushed sandalwood, herbs, sugar rice and oil are offered to the ceremonial fire. The “gath bandhan” takes place where scarves of the bride and groom are tied together symbolizing their eternal bond. This signifies their pledge before God to love each other and remain loyal. The couple then takes four “mangal pheras” or walk around the ceremonial fire, representing four goals in life: “Dharma”, religious and moral duties; “Artha”, prosperity; “Kama” earthly pleasures; “Moksha”, spiritual salvation. The couple also takes seven steps together to begin their journey, called the “saptapardi”. Then the ritual of “sindoor” takes place where the groom applies a small dot of vermilion, a red powder to the bride’s forehead and welcomes her as his partner for life. This signifies the completion of the marriage. The parents of the bride and the groom then give their blessings, “ashirwad” to the newly wed couple as they touch the feet of their parents. 

What might be the most suitable title for this reading passage?

The word "pigment" at the end of the first paragraph means ...........

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

It can be inferred from the passage that limestone deposits serve as the basis of .................