C. Permafrost
Permafrost is the layer beneath the "active layer". The active layer consists of soil that freezes and thaws every year. However, the requirement for permafrost is that it be frozen for two or more years consecutively. This is why permafrost exists in cold environments such as tundras.
The correct answer is - B. Beak size determines what the bird can eat.
The beak of a bird can come in many different shapes and sizes. It can be pointy, long, short, rounded, scythe-like, thin, thick... All of those shapes and sizes have a specific role, and that role is to enable the bird to feed itself with certain type of food source. Every food source requires certain type of beak in order for the bird to be efficient in getting its nutrition, so depending on hat the bird eats, we can easily see a pattern in the beaks, where birds that eat nuts have one strong and shorter beak, the ones that eat warms and insects have thin, pointy one, the predator birds have claw like, sharp beak...
Answer:
a
Explanation:
plants uses oxygen for respiration, so in that process respiration takes place and respiration in plants has to do with the conversion of oxygen to carbon dioxide which serves as a means of respiration and during respiration ATP is being produced which stands for Adeosine triphosphate
Receptor proteins, they then send out the signal to perform a task or duty
