DAV school class 7science ch 1,2,3fair please l will make you brainlist. and follow. class 7 DAV students help me.
Answers
Answer:
Ch - 1
essential notes :-
Food is essential for living organisms
Nutrients are 'taken in' through their food by living organisms and are utilised in their bodies.
- This process of obtaining, and utilising food by an organism, is known as nutrition.
The process of obtaining food is not the same in all organisms.
there are 3 types of nutrition-
- Heterotrophs
- Autotrophs
- Saprotrophs
Autotrophic nutrition- it includes plants as producers , which produce there own food.
Heterotrophic nutrition- Organisms dependent on another organisms for their food and survival .
Saprotrophic nutrition- organisms feed on dead and decaying matter.
- Plant makes there own food by the process of photosynthesis.
It includes green colour pigment consisting chlorophyll, CO2 and sunlight .
Glucose in form of carbohydrates and O2 is produced during this process.
Symbiotic Relationship
- 2 organisms live in close association and develop a Relationship that benefits both organisms.
like, algae and fungi lives in Symbiotic Relationship.
Ch - 2
Essential notes
On basis of food habits organisms are classify into 3 types :
- Herbivores
- Carnivores
- Omnivores
Herbivores - Dependent on plants .
Carnivores- Dependent on other animals
Omnivores- Eat plants as well as animals
Modes of nutrition in animals-
- Saprotrophic nutrition
- parasitic nutrition
- Holozoic nutrition
Intake of food by digestive system-
- Ingestion
- Digestion
- Absorption
- Assilimation
- Egestion