Define Diffusion.
Movement of molecules of solids, liquids and gases from a place of higher concentration to a place of lower concentration.
Biology
What is external fertilisation ?
Solution : The fusion of a male and a female gamete takes place outside the body of the female is called external fertilisation. It is very common in aquatic animals such as fish, starfish, etc.
What is an internal fertilisation ?
Solution : Fertilisation which takes place inside the female body is called internal fertilisation. Internal fertilisationoccurs in many animals including humans, cows, dogs and hens.
What is fertilisation ?
Solution : fusion of the female gamete (egg ) and the male gamete ( sperm ) is called fertilisation,
Question 10.
How does temperature, light intensity and wind affect transpiration?
Answer:Temperature: Transpiration is faster on hot summer days as compared to cold winters.Light intensity: The transpiration rate is increased due to the increase in light intensity.During daytime in the sunlight, the rate of transpiration is faster. This is because thestomata remain open to allow the inward diffusion of carbon dioxide for photosynthesis.During dark, the stomata …
Question 10.
How does temperature, light intensity and wind affect transpiration? Read More »
Question 9. Briefly explain, how transpiration helps in upward conduction of water in plants? (a) ………. (b) ……….
Answer:(a) Plants continuously absorb water through their roots. This water is sent up throughthe stem to all parts of the plant, including the leaves. Only a little amount, of water isretained in the plant or utilised by it in photosynthesis. The rest of it gets evaporated intothe atmosphere as water vapour through the stomata present …
Question 6.
Under what conditions do plant transpire (a) more quickly and (b) most slowly?
Answer:(a) Transpiration is faster on hot summer days as compared to cold winters.(b) Transpiration is reduced if the air is humid. Air cannot hold any water moleculeswhen it is already laden with moisture (humidity).
Question 5.
Define the terms:
(a) semi-permeable membrane
(b) osmosis
Answer: (a) Semi-permeable membrane: It is a membrane that allows the movement of solventmolecules (e.g. water molecules) through it but prevents the movement of soluteparticles (e.g. sugar or salt molecules).For example: Egg membrane, parchment membrane, cellophane paper etc. are semi-permeable membranes. (b) Osmosis: The diffusion of water molecules through a semi-permeable membranefrom a region where …
Question 5.
Define the terms:
(a) semi-permeable membrane
(b) osmosis Read More »
Question 3.
What do xylem vessels carry?
Answer:The xylem vessels carry the water and minerals absorbed by the roots to the stem and In test tube A the water level falls because the water was absorbed by the plant throughits roots dipped in water. Here no water loss occurs due to evaporation from the watersurface due to presence of oil.In test tube …