There are two types of polar climate: ET, or tundra climate; and EF, or ice cap climate. A tundra climate is characterized by having at least one month whose average temperature is above 0 °C (32 °F), while an ice cap climate has no months above 0 °C (32 °F).
This question is very good
The cytoplasm in a single-celled organism and the circulatory system in a human both transport substances throughout the organism
The correct answer is option A. They either match up with a receptor molecule on the surface of the cell or enter the cell through the membrane.
The intercellular signals are the signals, which transfer the signals from one cell to the another and the intracellular signals are those signals, which carries message within the cell.
The intercellular signals may or may not be transferred through the gap junctions. The chemical signals are one of the type of the cell signals. The chemical signalling molecules generally have a receptor on the cells, where these molecules can bind and can be cause the activation of the cell. The chemical signals can also enter into the cells through active transport and facilitated diffusion. So, these type of transports does not go through the Gap junction.
Ageing is the word that describes all that change as the organism evolve and it also includes growth !