<span>In aquatic ecosystems net primary productivity is related to</span>available sunlight and nutrients.
<span>if the oxygen poor blood mixes back with oxygen rich blood, that means that oxygen poor blood is not going back to the lungs to swap CO2 (carbon dioxide) with O2 (oxygen), and this swapping is vital to tissue survival, since oxygen is what keeps your tissues, muscles, and organs alive. so if this blood mixed, ultimately your organs are not receiving enough oxygen and will become starved of it, this can kill you and lots of people every year get heart surgery because their atrium or ventricles in their heart rupture (normally the valves</span>
Answer:
The correct answer is "There are several mechanisms that explain why a hormone have different effects in different cells. These mechanisms include: multiple receptors for the same hormone, a single receptor coupled to different pathways and hormones interacting with receptors for other molecules".
Explanation:
Hormones are among the most versatile molecules of the body, responsible for different biological processes such as human growth, sex development and metabolisms. Hormones are responsible of these complex biological processes because they have drastically different effects in different cells. There are several mechanisms that explain why a hormone have different effects in different cells. These mechanisms include:
- Multiple receptors for the same hormone. For instance, there are multiple receptor for dopamine, a hormone and neurotransmitter responsible for different functions such as movement, memory, sleep and motivation.
- A single receptor coupled to different pathways. Most hormone receptors act with a cascade of signaling. This in consequence results in a single receptor interacting with different molecules having multiple effects.
- Hormones interacting with receptors for other molecules. One example is the action of one metabolite of progesterone named allopregnanolone. This metabolite interacts with GABA-A receptor, which gives it anxiolitic properties.
Answer:
ISOTOPES
the same number of protons
but difference numbers of neutrons
IONS
because they have lost or gained one or more electrons