CBSE Questions for Class 9 Biology Diversity In Living Organisms Quiz 4 - MCQExams.com

• Gymnosperms and angiosperms are phanerogams.
• Phanerogams are seed-bearing plants. 
• Gymnosperms are distinguished from angiosperms by having naked ovules and seeds. 
• The ovules are not enclosed in an ovary and the seeds are not enclosed in a fruit. 
• In angiosperms or flowering plants, the seeds are enclosed in a fruit, and are known as "covered seeds".

• The gymnosperms are represented by perennial, evergreen, woody plants. Most of them are trees and some are shrubs. A few gymnosperms may be lianas (woody vine) or climbers. There are no herbs. Gymnosperms include one of the world's tallest trees, Sequoia sempervirens.

• Amphibians spend their lives in water and on land. There are more than 4,000 different kinds of amphibians. Members of this animal class are frogs, toads, salamanders, newts, and caecilians or blindworms.
• Before amphibians reach adulthood, they first experience a larval stage, where they breathe primarily through their gills. When they get older, they start to breathe through their lungs, which allows them to live on land. Hence, it is necessary for amphibians to live in both land and water.
  

Solution

Correct answer is option B.

Explanation for correct option:

• A classification is a division or category in a system which divides things into groups or types.
• There are 7 different taxonomical ranks in which organisms are grouped :  kingdom, phylum or division, class, order, family, genus, species.
• Species is considered as a basic unit of classification.

• In vascular plants, xylem is the principal water-conducting tissue and is made up of tracheary elements:-tracheids, vessels and xylem fibers. 
• In angiosperms, vessels are the main component of the xylem but in gymnosperms, vessels are absent hence the tracheids are the chief water conducting elements in the seedless vascular plants.

• Lady wears a dress to be attractive, to suit herself.
• Leaves are the site of food synthesis and gaseous exchange in trees.
• Feathers help birds to fly and keep their body warm. 
• Scales protect fish from the harsh external environment (from predators, as well as parasites, and water) whereas Skin also protects the internal organs of human body from the harsh external environment. Therefore, option D is correct. 

• All four options belong to biological classification, wherein species is a taxonomic rank that lies at the lowest level below family, genus & class. 
• It is the basic unit of classification. The organisms in rank species are mostly similar to one another and can interbreed.

So, the correct answer is option D.

• Pyrenoids are found in the chloroplasts of many algae, and in a single group of land plants, the hornworts. 
• Pyrenoids occur in many of the algae and are associated with the chloroplasts. Some of them are known to contain Rubisco, the enzyme that catalyzes the incorporation of inorganic CO$$_2$$ into carbohydrate. In these algae, pyrenoids probably function to fix carbon. In other algae, pyrenoids are the sites of carbohydrate (typically starch) storage. Starch and iodine react to produce a deep blue-black colour, so staining a thin algal prep with iodine will indicate the presence of pyrenoids.
• Spirogyra is a filamentous green alga in which the chloroplast has a characteristic spiral shape. In this photograph, you can see the chloroplast coiling against the outer edge of the cells. The numerous small round blobs along the edges of the chloroplast are the pyrenoids. The larger, faint blobs (they look like out-of-focus regions) that take up most of the volume of the cells in the filaments on the right are the nuclei, which are suspended in the interior of the cells.

• Green algae have chloroplasts that contain chlorophyll a and b, giving them a bright green color, as well as the accessory pigments beta carotene and xanthophylls, in stacked thylakoids. 
• The cell walls of green algae usually contain cellulose, and they store carbohydrates in the form of starch. 
• The end product of photosynthesis in these green algae is glucose that will be converted into starch before storage.

• Fucoxanthin is a xanthophyll, found as an accessory pigment in the chloroplasts of brown algae and most other heterokonts, giving them a brown or olive-green color. It is the principal pigment of Phaeophyceae.
• Phycocyanin is a pigment-protein complex from the light-harvesting phycobiliprotein family, along with allophycocyanin and phycoerythrin. It is an accessory pigment to chlorophyll. All phycobiliproteins are water soluble, so they cannot exist within the membrane-like carotenoids. 
• Phycoerythrin (PE) is a red protein-pigment complex from the light-harvesting phycobiliprotein family, present in red algae.
• Phycobilins are light-capturing pigments found in cyanobacteria.

• The eyespot or stigma is a photoreceptive organelle found in the flagellate of green algae like Chlamydomonas and some other unicellular photosynthetic organisms such as euglenoids.
• It allows the cells to sense light direction and intensity and respond to it by swimming either towards the light (positive phototaxis) or away from the light (negative phototaxis).  
• Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis. 
• Eyespots are the simplest and most common "eyes" found in nature, composed of photoreceptors and areas of bright orange-red pigment granules. 
• Signals relayed from the eyespot photoreceptors result in alteration of the beating pattern of the flagella, generating a phototactic response.

• They possess a chitinous exoskeleton that must be shed during growth.
  
• The paired appendages (e.g., legs, antennae) are jointed.
  
• The segmented bodies are arranged into regions, called as tagmata (e.g., head, thorax, abdomen).
  
• They have bilateral symmetry.
  
• The nervous system is ventral (belly) and the circulatory system is open and dorsal (back).
  

• The bodies of Arthropods are divided into a number of segments. However, few of these segments are sometimes fused to form integrated body parts known as tagmata. This process of fusion is called tagmosis. The head, thorax and abdomen are examples of tagmata. 
• Arthropods also have appendages with joints (the word "arthropod" means "jointed feet"). In early, primitive anthropods, each body segment was associated with a single pair of appendages (attachments). However, in most species, some appendages have been modified to form other structures, such as mouthparts, antennae, or reproductive organs. 
• Arthropod appendages may be either biramous (branched) or uniramous (unbranched).

• A maggot is the larva of a fly; it is applied in particular to the larvae of Brachyceran flies, such as houseflies, cheese flies and blowflies, rather than larvae of the Nematocera, such as mosquitoes and crane flies.
• Wriggler- Mosquito larvae.
• Grub- The larva of an insect, especially of a beetle; called also as grubworm.
• Caterpillar is the common name for the larvae of members of the order Lepidoptera. As with most common names, the application of the word is arbitrary and the larvae of sawflies commonly are called as caterpillars as well.