An organism uses outside raw materials mostly in the form of food and oxygen. The raw materials required by an organism can be quite varied depending on the complexity of the organism and its environment.
All plants give out oxygen during day and carbon dioxide during night”. Do you agree with this statement? Give reason
This is an incorrect statement. All plants carry on respiration throughout 24 hours and thus give out carbon dioxide throughout the 24 hours. But photosynthesis happens only in presence of sunlight and oxygen is released during daytime.
The rate of breathing is slower in terrestrial organisms as compared to aquatic organisms. This is due to the fact that in water, the amount of oxygen is less as compared to air while in aquatic organisms the rate of breathing is faster.
Match the words of Column (A) with that of Column (B)
|(a) Phloem||(i) Excretion|
|(b) Nephron||(ii) Translocation of food|
|(c) Veins||(iii) Clotting of blood|
|(d) Platelets||(iv) Deoxygenated blood|
Ans. (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)
Nephrons are the basic filtering units of kidneys. Each kidney possesses large number of nephrons, approximately 1-1.5 million. The main components of the nephron are glomerulus, Bowman's capsule, and a long renal tubule.
Structure of a nephron
Functioning of a Nephron:
The blood enters the kidney through the renal artery, which branches into many capillaries associated with glomerulus.
The water and solute are transferred to the nephron at Bowman's capsule.
In the proximal tubule, some substances such as amino acids, glucose, and salts are selectively reabsorbed and unwanted molecules are added in the urine.
The filtrate then moves down into the loop of Henle, where more water is absorbed.
From here, the filtrate moves upwards into the distal tubule and finally to the collecting duct. Collecting duct collects urine from many nephrons.
The urine formed in each kidney enters a long tube called ureter. From ureter, it gets transported to the urinary bladder and then into the urethra.
Fish can take in oxygen which is dissolved in water. For this, they show adaptation in the form of gills. But fish does not have the ability to utilize oxygen from air. Due to this, a fish can comfortably live in water but dies when it is taken out of water.