Comment upon the gametic exchange in ear | Class 11 Biology Chapter Structural Organisation in Animals, Structural Organisation in Animals NCERT Solutions

Why earthworm is called the friend of farmer?
 

Stratified epithelial cells have limited role in secretion. Justify their role in our skin.
 

The digestive system of frog is made of the following parts. Arrange them in an order beginning from mouth.
Mouth, oesophagus, buccal cavity, stomach, intestine, cloaca, rectum, cloacal aperture
 

How many times do nymphs moult to reach the adult form of cockroach?
 

Name the different cell junctions found in tissues.
 

Define a taxon. Give some examples of taxa at different hierarchical levels.

What are the steps involved in formation of a root nodule?

Name the pathological condition when uncontrolled cell division occurs.
 

Aquatic animals generally are ammonotelic in nature where as terrestual forms are not. Comment.
 

Name the cells/tissues in human body which
a. exhibit ameboid movement
b. exhibit ciliary movement

How do you distinguish between a skeletal muscle and a cardiac muscle?

Which of the following is correct:
(a) Cells of all living organisms have a nucleus.
(b) Both animal and plant cells have a well defined cell wall.
(c) In prokaryotes, there are no membrane bound organelles.
(d) Cells are formed de novo from abiotic materials.

Mitosis results in producing two cells which are similar to each other. What would be the consequence if each of the following irregularities
occur during mitosis?
a. Nuclear membrane fails to disintegrate
b. Duplication of DNA does not occur
c. Centromeres do not divide
d. Cytokinesis does not occur.