Question

answer the following in 4-5 sentence each

1) how does infectious disease spread? explain with example

2) write schematic representation of carbon cycle

3) write short note on cattle farming

4) give scientific reasons

a) we can get the smell of perfume sitting several metres away

b) steam produces severe burns than boiling water

5) mention properties of metals

6) calculate the molecular mass of the following
Carbon= 12. hydrogen=1. Oxygen=16

a) co2 b) ch4

Answer 1

Ans-1 The infection disease caused by dispersion bacteria and disease causing microorganisms from one body to another or by physical contact.Ex-Common cold.
Ans-2The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere , pedosphere, geosphere here , hydrosphere, and atmosphere of the Earth.
Ans-3The breeding and raising of cattle or livestock like cow,pig,sheep,goat,horse ect.for the production of meat,milk and for other agricultural use is known as cattle farming.
Ans-4 a)It is bcoz perfume is volatile. It has a high degree of vaporisation, the vapours diffuse in all direction easily. So, we can smell the perfume sitting several metres away.
Ans-b It is bcoz steam has more energy than boiling water. It possesses the additional latent heat of vaporization. Therefore, burns produced by steam are more severe than those produced by boiling water.
Ans-5 The properties of metals are:
1-If you polish it it looks shiny and silvary looking
2- its structure is closely backed.
3-its ionisation energy is low
4-It is naturlly in combined states
Ans-6 a) (i)Molecular mass of CO2 =Atomic Mass of C+2 × Atomic Mass of O=12+32=44 
Ans-b)Molecular mass of CH4 =Atomic Mass of C+4 × Atomic Mass of H=12+4=16 
By
Aanya Kandwal

Answer 2

Check in Xamidea it's there given in brief. Hope it helps..