Ostrich eggshell is composed of 96% crystalline calcite and 4% organic material, mostly proteins. The thickness is made up of three different layers that vary in structure and thickness. The hardness of the shell is 3 on the Mohs scale. Pretty solid!
Using the concept that :
<span>The skin cell has twice the number of chromosomes as the sperm cell has.
</span>Hence,
<span>The sperm cell has 39 chromosomes.
The skin Cell will have = 39 x 2
= 78 </span><span>chromosomes.</span>
Answer:
Kidneys : helps in forming urine
Ureter : They are connected to kidney and by peristaltic action transports urine from kidneys to bladder .
Urinary bladder : It is an hollow sac that holds the urine .
Urethra : transports urine from the bladder to outside of the body .
Explanation:
The human excretory system consists of : Kidney ,ureter ,urinary bladder and urethra .The figure is shown below .
Now , as far as functions are concerned we have :
Kidneys : They have excretory units called nephrons that further consist of :
- Bowman's capsule
- PCT (Proximal convoluted tubule )
- DCT (Distal convoluted tubule)
- CT (collecting tubule )
In nephrons urine is formed and via ureter it is transported to a hollow sac like structure called urinary bladder .
This bladder has muscles that cant remain contracted up to longer period )and then voluntary and involuntary it is excreted through urethra .
The process of passing urine is called Micturition .
