1. Paleozoic era
2. Cenozoic era
3. Mesozoic era
4. Pleistocene era
Option “3” is correct Dinosaurs lived between 230 and 65 million year ago, in a time known as Mesozoic Era.
502. The red colour of the red sea is due to the presence of :
1. Moss
2. Bacteria
3. Algae
4. Fungi
Option “3” is correct The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. An algae, of phylum Cyanobacteria called Trichodesmium erythraeum is present in this sea. It contains abundant quantities of pigments, phycobilin, phycoerythrin and phycocyanin, due to which the sea appears red or pinkish.
503. Plants adapted to dry climate are known as-
1. Epiphyte
2. Xerophyte
3. Hydrophytes
4. Mean plants
Option “2” is correct A xerophyte is a species of plant that has adapted to survive in a dry environment.
504. Which one of the following is not a plant hormone?
Option “3” is correct A hormone produced in the pancreas by islets of Langerhans, which regulates the amount of glucose in the blood. The lack of insulin causes diabetes.
Option “3” is correct Hydrophytes or aquatic plants are plants that have adapted to live in an aquatic environment (saltwater or freshwater). They are also referred as macrophytes. These plants require special adaptations for living submerged in water or at the water’s surface. Plants growing on saline soils or water are called halophytes.
506. Fish generally breathe through-
1. Skin
2. Nose
3. Gills
4. Fins
Option “3” is correct Fish use gills to breath and gills can only bring in oxygen when moist. Out of water, a fish’s gills dries out and then the fish dies.
507. The sugar present in DNA is :
1. Glucose
2. Fructose
3. Deoxyribose
4. None of these
Option “3” is correct The deoxyribose is sugar found in DNA. It is a variant of five carbon sugar called ribose. The DNA is an informational molecule found mainly in the nucleus of the cell.
508. Delonix regia Rafin is the scientific name of –
1. Banyan
2. Gulmohar
3. Tamarind
4. Chiku
Option “2” is correct Delonix regia Rafin is the scientific name of Gulmohar.
Option “4” is correct Platelets, also called thrombocytes are a component of blood whose function (along with the coagulation factors) is to stop bleeding by clumping and clotting blood vessel injuries.
