Explanation:
Sea otters are an iconic species, representing the beauty and diversity of marine life found along California’s coastline. They’re also considered a keystone species because of their critical importance to the health and stability of the nearshore marine ecosystem. They eat sea urchins and other invertebrates that graze on giant kelp.
Answer:
The same ligand can bind to different receptors causing different responses (e.g.. acetylcholine). On the other hand, different ligands binding to different receptors can produce the same cellular response (e.g. glucagon, epinephrine).
Explanation:
Answer:
Due to presence at early days of the planet.
Explanation:
We only find the remains of single celled organisms in the oldest fossils because the single celled organisms are the organisms that were present in the early days of this planet. These single celled microbes were present about 3.7 billion years ago while on the other hand, the oldest rocks are only a little older i. e. 3.8 billion years so these single celled organisms are considered as oldest fossils on this planet.
