प्रकृति ने पृथ्वी पर जीवन के लिये प्रत्येक जीव के सुविधानुसार उपभोग संरचना का निर्माण किया है. परन्तु मनुष्य ऐसा समझता है कि इस पृथ्वी पर जो भी पेड़-पौधे, पशु-पक्षी, कीट-पतंगे, नदी, पर्वत व समुद्र आदि हैं, वे सब उसके उपभोग के लिये हैं और वह पृथ्वी का मनमाना शोषण कर सकता है. यद्यपि इस महत्वाकांक्षा ने मनुष्य को एक ओर उन्नत और समृद्ध बनाया है तो दूसरी ओर कुछ दुष्परिणाम भी प्रदान किये हैं, जो आज विकराल रुप धारण कर हमारे सामने खडे हैं. पृथ्वी पर प्रकृति शोभा के लिये पर्यावरण की सुरक्षा विकास का एक अनिवार्य भाग है. पर्यावरण की समुचित सुरक्षा के अभाव में विकास की क्षति होती है. इस क्षति के कई कारण हैं. यांत्रिकीकरण के फलस्वरूप कल-कारखानों का विकास हुआ. उनसे निकलने वाले उत्पादों से पर्यावरण का निरन्तर पतन हो रहा है. कारखानों से निकलने वाले धुएं से कार्बन मोनो ऑक्साइड और कार्बन डाई ऑक्साइड जैसी गैसें वायु में प्रदूषण फैला रही हैं, जिससे आंखों में जलन, जुकाम, दमा तथा क्षयरोग आदि हो सकते हैं.

दिसम्बर 1984 की भोपाल गैस रिसाव त्रासदी के जख्म अभी भी भरे नहीं हैं. वर्तमान में भारत की जनसंख्या एक अरब से ऊपर तथा विश्व की छः अरब से अधिक पहुंच गई है, इस विस्तार के कारण वनों का क्षेत्रफल लगातार घट रहा है, 10 साल में लगभग 24 करोड़ एकड़ वन क्षेत्र समाप्त हो गया है. नाभिकीय विस्फोटों से उत्पन्न रेडियोएक्टिव पदार्थों से पर्यावरण दूषित हो रहा है. अस्थि कैंसर, थायरॉइड कैंसर त्वचा कैंसर जैसी घातक बीमारियां हो रही हैं. उपयुक्त विवेचना से स्पष्ट है कि पर्यावरण सम्बन्धी अनेक मुददे आज विश्व की चिन्ता का विषय हैं.

1. Storage Leaves: Some plants of xerophytic habitats and members of the family Crassulaceae generally have highly thickened and succulent leaves with water storage tissue. These leaves have large parenchymatous cells with big central vacuole filled with hydrophilic colloid. This kind of adaptation helps plants to conserve very limited supply of water and resist desiccation (drying up).

2. Leaf Tendrils: In weak- stemmed plants, leaf or a part of leaf gets modified into green thread­like structures called tendrils which help in climbing around the support.

3. Leaflet Hooks: In Bignonia unguiscati the three terminal leaflets of leaf get modified into claw like hooks which help in climbing .

4. Leaf Roots: In case of Salvinia three leaves are present at one node. Out of these two leaves are normal and third gets modified into adventitious roots which help in floating over the surface of water

NOTICE

POSTER MAKING COMPETITION

A poster making competition is going to be held in our school on 8th january. The topic for the posters are:-
1.Women Empowerment
2.Save Girl Child
3.Make in India
4.Digital India
Prizes will be given on the day of the competition. Intetested students can give their names to the vice principal.

Name
XYZ

We know that in ice, each oxygen atom is surrounded by four hydrogen atoms in such a way that the two hydrogen atoms are linked to an oxygen atom by covalent bonds whereas the other two hydrogen atoms are linked by hydrogen bonds. In ice (solid state), a water molecule is associated with four other water molecules through hydrogen bonding in a tetrahedral manner. This gives rise to open cage-like structure which prevents the close packing of molecules (lower density). When ice absorbs heat and melts to form water, the hydrogen bonds break and close packing of water molecules takes place. Due to this close packing, the density of water is higher than that of ice and hence ice floats over water.

Definition: This commonly-used phrase stands for 'all other things being unchanged or constant'. It is used in economics to rule out the possibility of 'other' factors changing, i.e. the specific causal relation between two variables is focused.

The algal component of the lichen is called phycobiont and fungal component is known as mycobiont. Phycobiont prepare food for fungi and mycobiont provides shelter and absorb mineral nutrients and water for its partner.

The ultrastructure of the phycobionts is similar to that of free-living algae. The mycobionts displayed structural differences in their walls which apparently are unrecorded for fungus hyphae, resulting in a striking polymorphism of the hyphae.

The person who carries on wholesale trade is known as wholesaler. A wholesaler provides many valuable services to the manufacturer as well as the retailer.

Services provided by wholesalers are as follows:

1. Buying and assembling : The wholesaler buys the product from the manufacturer and collects the same at one place and supplies goods to the retailers according to their requirement.
2. Storage function : The wholesaler also performs the storage function. The goods are purchased by the wholesalers from the manufacturers and stored at warehouses in order to meet the demand of retailers. The wholesalers act as bridge between the production and consumption of goods.
3. Breaking the bulk : The wholesaler purchases goods from manufacturers in bulk and avails discounts. He sells goods in small quantities to the retailers which saves the retailers from maintaining large stocks.
4. Advertisement : A wholesaler undertakes advertising and sales promotion of the product which automatically result in the increase in sales.
5. Market information : Wholesalers inform the retailers about the introduction of new products in the market. He also gets feedback from the retailers about the needs and preferences of customers. He passes the information to the producer to make necessary changes in the products.
6. Risk bearing : The wholesalers have to maintain optimum levels of stock in their godowns to meet the demands of the retailer. The retailer’s risk of maintaining godowns, price fluctuations, etc., are reduced to a great level.

Abscisic acid is called stress hormones as it induces various responses in plants against stress conditions.

It increases the tolerance of plants toward various stresses. It induces the closure of the stomata during water stress. It promotes seed dormancy and ensures seed germination during favourable conditions. It helps seeds withstand desiccation. It also helps in inducing dormancy in plants at the end of the growing season and promotes abscission of leaves, fruits, and flowers.