In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better’ body design? Why or why not?
A better body design is, which have more complexity in their structural and developmental characteristics and have control on their body. Every organism has their body design according to their needs for survival in the environment. Among all four organisms bacteria, spider, fish and chimpanzee- chimpanzees have more complex body structure and can do more functions according to the evolutionary terms. But all four organisms have better body design according to their needs to adapt to the environment. So, we cannot decide which organisms have better body design in the evolutionary terms.
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Outline a project which aims to find the dominant coat colour in dogs.
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
How is the sex of the child determined in human beings?
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
Calculate the number of electrons constituting one coulomb of charge.
What is an homologous series? Explain with an example.
Why is variation beneficial to the species but not necessarily for the individual?
A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
Why does menstruation occur?
What are the limitations of the energy that can be obtained from the oceans?
Which of the following correctly describes the magnetic field near a long straight wire?
(a) The field consists of straight lines perpendicular to the wire.
(b) The field consists of straight lines parallel to the wire.
(c) The field consists of radial lines originating from the wire.
(d) The field consists of concentric circles centred on the wire.
Which one of the following types of medicines is used for treating indigestion?
(a) Antibiotic
(b) Analgesic
(c) Antacid
(d) Antiseptic
A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.
Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
Compare and contrast fossil fuels and the Sun as direct sources of energy.
What were the criteria used by Mendeléev in creating his Periodic Table?
Name two metals which are found in nature in the free state.