CBSE ADDA

1. Why do mountaineer carry oxygen cylinder while climbing? Ans: This is because amount of oxygen at high altitude and become difficult to breadth. 2.  Why does smell of perfumes reach us several meters away? Ans: This is because air is continuously moving it takes the particle of perfumes along with it. 3. Why does crocodile keep it snout out of the water while resting? Ans: Crocodile keeps it snout out of the water while resting to breathe through nostril. 4. Why do we see bubbles in water before it starts boiling? Ans: This is because dissolved air is expelled out o heating. 5. Why do animals that live in holes or borrow in soil breadth? Ans: They breadth in oxygen present between the soil partials. 6. What is the role of air in water cycle? Ans: Air helps the water vapour to rise up to form cloud. 7. What does air bubbles coming out of soil, when pt in water indicates? Ans: The presence of air 8. Why long chimneys are installed in factories?

CBSE 6 th Chapter -Waste  (Garbage In, Garbage Out ) • Introduction • Segregation of wastes • Management of biodegradable wastes • Composting, Landfills - Structure of a landfill • Management of Non-Biodegradable Wastes • Reduce, Reuse, Recycle - Recycling of Plastics,  Recycling of paper Garbage Disposal A large, low-lying area used to dispose garbage is known  as a dump.  A garbage dump is also used as landfill. Garbage collectors collect waste and then dispose it at  garbage disposals.  Garbage dumps have flies, cockroaches and mosquitoes, and later turn into breeding  grounds for micro-organisms that may cause diseases. That is why these garbage dumps are usually located  on the outskirts of a city. Components of garbage: Garbage has useful and non-useful components. ü   Useful garbage components are those that can be decayed easily. The process of decaying is known as  composting. Useful garbage components are fruit and vegetable waste, pl

(I) answer the following questions in one word 1. What is the age of puberty in girl? Ans: 10 – 12 years 2. Which gland secretes Corticoid hormones? Ans: Adrenal Glands 3. What types of fertilization takes place in Man? Ans: Internal Fertilization 4. What is the other name of Endocrine garland? Ans; Ductless gland 5. What is the term used for development of Ovum without fertilization? Ans: Parthenogenesis 6. Name the hormones secreted by pineal glands? Ans: Melatonin 7. Which gland is called master glands? Ans: Pituitary Gland 8. When chromosome is not sex chromosomes, what is it called? Ans: autosomes 9. Name the term used for having X and Y chromosomes. Ans: Sperm gamete 10. Name the hormones secreted by testes? Ans: Testosterone (II) Answer the following questions in brief 1. Why does our body changes when we reach to teens? Ans: when we reach to teens, Endocrine system of or body regulate the release of hormo

1. Which animal tissue is commonly known as packaging tissue? [1] Ans: Areolar Tissue 2. What do you mean by photoperiod? Name two processes that are dependent on photoperiod.[2] Ans: Photoperiod is related to exposure of plants to the duration of sunlight. Germination, growth and flowering (any two) in case of plants are dependent on Photoperiod. 3. What will happen if:  i) the skin epithelium is not stratified.  ii) Stratified squamous epithelium lines blood vessels. [2] Ans: i) There will be no protection to the inner layers and wear and tear will be more.        ii) The exchange of substances through selectively permeable surface cannot take place. 4. Name the target organ/organ system of AIDS virus. What is the cause of death in case of people suffering from AIDS? [2] Ans: Lymph nodes/Immune System. In absence of a strong Immune system ,minor infections can turn in to serious problems. 5.To increase productivity per unit area ,the farmers grow two differe

Chapter – 3 ATOMS AND MOLECULES  1.  An old man and a scientist were talking about a deserted house. The old man was sure that it was haunted by ghosts, but the scientist discarded the view saying no one had ever seen a ghost. The old man was annoyed and challenged the scientist about existence of atoms, sub-atomic particles which also could not be seen. · Name the three sub-atomic particles and their discoverers. · Whose viewpoint do you support and why? 2.  An activity was conducted in a classroom where students held placards with symbols and valency of the elements separately. Each student held two placards, one with the symbol in the right hand and other with the valency in the left hand. · Which placards will be required for formation of sodium chloride ( both symbol as well as valency). · Which qualities are required in the student to perform such a group activity? 3.  Two class IX students, Kaveri and Nalin, were asked to take 5.3 g of sodium carbonate and 6g

CBSE-CH: Floatation GRAVITATION]                              Q1.While passing nearby a pond, some students saw a drowning man screaming forhelp. They alerted another passerby, who immediately threw an inflated rubber tube in the pond. The man was saved.· Why the passerby did use inflated rubber tube to save the  drowning man? ·Write the principle involved here.· Which qualities shown by the students and the passerby do you identify that helped in saving the drowning man? Q2.You received  an e-mail from  a friend living in  a coastal town. He shared an experience with you that recently, while swimming on the coastline of the sea in common swimming attire, he thought of going deeper inside the sea. He was asked to abstain from delving deeper into the sea by the rescue personnel. Respond  to the following questions using the information provided above.Why the rescue personnel asked your friend not to swim deeper inside the sea? · What values were exhibited by the rescue personne

Q. Explain the process of waste water treatment? Ans: The wastewater is treated through physical, chemical, and biological processes to remove the physical, chemical and biological contaminants. Physical - separates the large waste Biological- Adding of microorganisms to digest waste and produce oxygen in water Chemical- Chlorine and other chemicals are added into the water to finally purify it. Q. what is sewage? Ans: Wastewater is generated during various activities in homes, industries, hospitals, offices, and laundry services etc. This waste water is called sewage. Q. Explain the vercomposting toilet ?            Ans: Vermicomposting toilets are those which do not use water and are very environment friendly. They can be utilized in areas where water is a scarcity and can also be used in forests and other areas where sewage lines have not been built. This process uses worms for decomposition of waste. The waste is degraded in a container. Q. what are the p