Because the melting/freezing point is the point at which the particles in a substance begin to go through the phase change
so for example at 0 degree's Celsius water starts to freeze, but at the same time also melts, its sorta like some of the particles are freezing while the others are melting at the same time, but if you go above 0 degrees then it melts, and if you go below it freezes
They have different types of cell walls and cell membranes.
the answer you put is right
C.
Every change in a species is coded within the DNA. But the bird had lost a toe an accident. So the toe-loosing-option isn't true because not every bird looses his toe.
(Example: If a women gets bitten by a snake on the arm and gets the arm removed from her body and then in a year or so has a baby with her new husband. The baby won't be born with one arm because his/her mother lost her arm.) <span />
Question: Which of the following are appropriate units for power?
A) newton·meter
B) watt
C) H.P./sec
D) joule/sec
Answer:
Watt and Joule/sec are the appropriate units for power.
Explanation:
As per the question, the physical quantity given is power.
The power is defined as the rate of consumption of energy or the rate of doing work.
Let us consider W is the amount of work done by a body in time t .
Mathematically the power of that body is written as -
power 
The unit of work is joule and the unit of time is second.
Hence, the unit of power is joule/sec.
we know that one joule/sec. = one watt.
Hence, watt is also another unit of power. Newton-metre can not be a unit of power . It may be considered as a unit of work.
Similarly H.P/sec is also not a unit of power. Here H.P stands for horse power which is another unit of power . Hence, joule/sec. and watt are the appropriate units of power.