Protista Organisms are most closely related to Archeabacteria.
To prevent blood flowing back after each heartbeat. They ensure that the blood flows only in one direction (back to the heart).
Agonist/antagonist
Agonist are drugs that bind and activate a receptor with effecting the response.If the effect results in maximum response it is considered as full agonist. However if the drug that binds to the receptor results only into partial efficacy in relation to the full activation of the receptor, this is considered as partial agonist.
Antagonist are drugs that blocks a biologic response of a hormone or another drug. They usually have affinity to the receptors but has no efficacy. This drug will just inhibit the activation of the receptors by the aganist.
Answer:
Option B
Explanation:
Both the US industrialist John D. Rockefeller and Andrew Carnegie believed that the law of nature govern even the industrial , business or corporate sector. As in a wild forest, strongest animal survives by feeding the weak animals, like wise the business/industries/corporation of large size survive by feeding or eliminating the smaller ones. They think that this is not at all evil but it is as per the law of nature.
Thus, option B is correct.
The answer is False.
Although, there are some evidence that suggests that species from million years ago possessed both gills and lungs. For example is the Acanthostega Gunnari, one of the oldest species discovered with four limbs. The creature is a salamander-like creature found in Greenland hundreds of million years ago. Although the specie can walk on land but the finding characterized the creature primarily as a fish.