(i) Homologous organs. Homologous organs are those organs which are formed on the same fundamental structural plan but they differ in their shapes because they have to function differently. Example: Forelimbs of frog and bird. (ii) Analogous organs. Analogous organs are structurally and developmentaRead more
(i) Homologous organs. Homologous organs are those organs which are formed on the same fundamental structural plan but they differ in their shapes because they have to function differently.
Example: Forelimbs of frog and bird.
(ii) Analogous organs. Analogous organs are structurally and developmentally quite different from each other i.e., they have different origins.
But they performs similar functions in different animals.
Example: The wings of a bird and wings of a bat.
(iii) Fossils. The remains or impressions of dead and decayed plants and animals are called fossils. Fossils tell us how new species are developed from the old one.
Example: Fossils of dinosaurs.
Three advantages of vegetative propagation: (i) Plants which do not produce viable seeds can be propagated by this method. (ii) Plants raised by this method can bear flowers and fruits earlier than those produced from seeds. (iii) Superior quality of plants can be obtained.
Three advantages of vegetative propagation:
(i) Plants which do not produce viable seeds can be propagated by this method.
(ii) Plants raised by this method can bear flowers and fruits earlier than those produced from seeds.
(iii) Superior quality of plants can be obtained.
Placenta: Placenta is a specialized tissue embeddded in the uterine wall. It contains villi on the embryo's side and blood spaces on the mother side. Function: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.
Placenta: Placenta is a specialized tissue embeddded in the uterine wall. It contains villi on the embryo’s side and blood spaces on the mother side.
Function: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.
Elements P,Q R and S are the elements of third period, these must have three filled shells. Electronic configuration of R: 2,8,5 Valency of R: 8-5 = 3 Electronic configuration of P: 2,8,1 Electronic configuration of S: 2,8,7 :Formula of the compound formed by the combination of P and S: PS/NaCI.
Elements P,Q R and S are the elements of third period, these must have three filled shells.
Electronic configuration of R: 2,8,5
Valency of R: 8-5 = 3
Electronic configuration of P: 2,8,1
Electronic configuration of S: 2,8,7
:Formula of the compound formed by the combination of P and S: PS/NaCI.
Advantages of conserving water in the form of ground water: (i) It does not evaporate. (ii) Spreads out to recharge wells. (iii) Provides moisture for vegetation over a large area. (iv) Does not provide breeding ground for mosquitoes. (v) Remain protected from contamination from human excreta, etc.
Advantages of conserving water in the form of ground water:
(i) It does not evaporate.
(ii) Spreads out to recharge wells.
(iii) Provides moisture for vegetation over a large area.
(iv) Does not provide breeding ground for mosquitoes.
(v) Remain protected from contamination from human excreta, etc.
Describe any three methods of tracing evolutionary relationship among arganisms.
(i) Homologous organs. Homologous organs are those organs which are formed on the same fundamental structural plan but they differ in their shapes because they have to function differently. Example: Forelimbs of frog and bird. (ii) Analogous organs. Analogous organs are structurally and developmentaRead more
(i) Homologous organs. Homologous organs are those organs which are formed on the same fundamental structural plan but they differ in their shapes because they have to function differently.
See lessExample: Forelimbs of frog and bird.
(ii) Analogous organs. Analogous organs are structurally and developmentally quite different from each other i.e., they have different origins.
But they performs similar functions in different animals.
Example: The wings of a bird and wings of a bat.
(iii) Fossils. The remains or impressions of dead and decayed plants and animals are called fossils. Fossils tell us how new species are developed from the old one.
Example: Fossils of dinosaurs.
List Three advantages of vegetative propagation.
Three advantages of vegetative propagation: (i) Plants which do not produce viable seeds can be propagated by this method. (ii) Plants raised by this method can bear flowers and fruits earlier than those produced from seeds. (iii) Superior quality of plants can be obtained.
Three advantages of vegetative propagation:
See less(i) Plants which do not produce viable seeds can be propagated by this method.
(ii) Plants raised by this method can bear flowers and fruits earlier than those produced from seeds.
(iii) Superior quality of plants can be obtained.
What is placenta? Explain its function in humans.
Placenta: Placenta is a specialized tissue embeddded in the uterine wall. It contains villi on the embryo's side and blood spaces on the mother side. Function: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.
Placenta: Placenta is a specialized tissue embeddded in the uterine wall. It contains villi on the embryo’s side and blood spaces on the mother side.
See lessFunction: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.
Four elements P,Q,R and S belong to the third period of the Modern Periodic Table and have respectively 1, 3, 5 and 7 electrons in their outermost shells. Write the electronic configurations of Q and R and determine their valencies. Write the molecular formula of the compound formed when P and S combine.
Elements P,Q R and S are the elements of third period, these must have three filled shells. Electronic configuration of R: 2,8,5 Valency of R: 8-5 = 3 Electronic configuration of P: 2,8,1 Electronic configuration of S: 2,8,7 :Formula of the compound formed by the combination of P and S: PS/NaCI.
Elements P,Q R and S are the elements of third period, these must have three filled shells.
See lessElectronic configuration of R: 2,8,5
Valency of R: 8-5 = 3
Electronic configuration of P: 2,8,1
Electronic configuration of S: 2,8,7
:Formula of the compound formed by the combination of P and S: PS/NaCI.
List four advantages of conserving water in the form of ground water.
Advantages of conserving water in the form of ground water: (i) It does not evaporate. (ii) Spreads out to recharge wells. (iii) Provides moisture for vegetation over a large area. (iv) Does not provide breeding ground for mosquitoes. (v) Remain protected from contamination from human excreta, etc.
Advantages of conserving water in the form of ground water:
See less(i) It does not evaporate.
(ii) Spreads out to recharge wells.
(iii) Provides moisture for vegetation over a large area.
(iv) Does not provide breeding ground for mosquitoes.
(v) Remain protected from contamination from human excreta, etc.