MEDIUM
12th CBSE
IMPORTANT
Earn 100

Explain, taking 'Prickly pear' (cactus) as an example, why new exotic species when introduced into a geographical area become invasive and the biological control method adopted to bring them under control.
 

Important Questions on Model Question Papers 1

MEDIUM
12th CBSE
IMPORTANT
Xam Idea Biology>Chapter 18 - Model Question Papers 1>MODEL QUESTION PAPER>Q 24
Why do certain organisms exhibit the phenomenon camouflage? Support your answer with two examples.
HARD
12th CBSE
IMPORTANT
Xam Idea Biology>Chapter 18 - Model Question Papers 1>MODEL QUESTION PAPER>Q 25
Describe any four devices which have been observed in plants to achieve cross-pollination and discourage self-pollination.
MEDIUM
12th CBSE
IMPORTANT
Xam Idea Biology>Chapter 18 - Model Question Papers 1>MODEL QUESTION PAPER>Q 25
State what would continued self-pollination result in.
MEDIUM
12th CBSE
IMPORTANT
Xam Idea Biology>Chapter 18 - Model Question Papers 1>MODEL QUESTION PAPER>Q 25
Explain the structure, function and significance of the placenta between the fetus and a maternal body in humans.
MEDIUM
12th CBSE
IMPORTANT
Xam Idea Biology>Chapter 18 - Model Question Papers 1>MODEL QUESTION PAPER>Q 26
Name the types of ribonucleic acids and mention their functions.
MEDIUM
12th CBSE
IMPORTANT
Xam Idea Biology>Chapter 18 - Model Question Papers 1>MODEL QUESTION PAPER>Q 26
Describe the process of transcription in prokaryotes.
MEDIUM
12th CBSE
IMPORTANT
Xam Idea Biology>Chapter 18 - Model Question Papers 1>MODEL QUESTION PAPER>Q 26

What are fossils? Explain how palaeontological evidence shows that evolution of life forms has indeed taken place on Earth.

HARD
12th CBSE
IMPORTANT
Xam Idea Biology>Chapter 18 - Model Question Papers 1>MODEL QUESTION PAPER>Q 27
Differentiate between detritus and grazing food chains.