What criteria do we use to decide whether something is alive?
All the living organisms show various types of processes during their life. This shows that they are alive, not a non- living organism or shows the assurance that they are not dead. When the organism is alive, it shows various types of processes like growth, movement, adaptations or the struggle for survival during the extreme stress conditions, respiration, reproduction, hormonal control and coordination processes, digestion, excretion and circulation. These processes ensure that something is alive.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
How is the amount of urine produced regulated?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
What are the differences between autotrophic nutrition and heterotrophic nutrition?
What are outside raw materials used for by an organism?
What would be the consequences of a deficiency of haemoglobin in our bodies?
What are the components of the transport system in highly organised plants?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Where do plants get each of the raw materials required for photosynthesis?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.
What is the role of decomposers in the ecosystem?
What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.
Use the data in Table 12.2 to answer the following –
(a) Which among iron and mercury is a better conductor?
(b) Which material is the best conductor?
List two methods of producing magnetic fields.
Compare the power used in the 2 Ω resistor in each of the following circuits:
(i) a 6 V battery in series with 1 Ω and 2 Ω resistors, and (ii) a 4 V battery in parallel with 12 Ω and 2 Ω resistors.
What are oxidising agents?
What are plant hormones?
The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?