Answer:
lead pencils (graphite)
fertilizer (potassium, sodium, calcium)
chalk (gypsum)
flashbulb (zirconium)
window glass/mirrors (silica)
table salt (halite)
Explanation:
The correct answer is d. spinal cord.
Spinal cord is a bundle of neurons which starts from the brain and runs down the entire length of the back of the body. The spinal cord acts as a main means to transmit the messages between the brain and the body.
Sensory or efferent neurons carry the information from the perimeter of the body and pass to the central nervous system whereas the motor or efferent neurons act as a communication channel and carry the information from the nervous system to various glands and muscles.
With fossils, scientists can use carbon dating to determine the approximate age of whatever fossil they have.
It must be able to store water for long periods of time
