I think the correct answer is D
Answer:
The reflex arc follows this sequence of events
1. sensory receptor activation
2. sensory neuron activation
3.information processing
4. motor neuron activation
5. effector response
Explanation:
Reflex arc is the pathway of nerves during a reflex action. An example of a reflex arc is when we accidentally touch a hot object. First, the receptor in the skin detects a stimulus in this case the change in temperature. Second, the sensory neuron transmit the electrical impulses to the Central Nervous System for information processing. Then relay neurons connect sensory neurons to motor neurons. Third, motor neurons sends electrical impulses to an effector wherein the effector produces a response ( muscle contracts to move the hand away from the hot object. This happens in a split of seconds.
Answer:
Direct observation of evolutionary change: creation of drug-resistant bacteria.
Fossil record: discovery of transitional forms of animals, discovery of shells of extinct organisms
Homology: similarities in mammalian forelimbs, identical genetic code in fireflies and tobacco plants, vestigial pelvis in right whales
Biogeography: resemblance of endangered island species to neighboring mainland species,
Answer:
Astronomers can use telescopes to look at very distant galaxies. This is how they see what the Universe looked like a long time ago. This is because the light from distant parts of the Universe takes a very long time to reach us. From these observations, it seems the physical laws and constants of the Universe have not changed.
Physicists are currently unsure if anything existed before the Big Bang. They are also unsure whether the size of the Universe is infinite.
