Answer:
crust, mantle, and the core
Explanation:
The correct answer is D. temperature difference in the mantle I am an Online Middle Schooler and I got it right
Temperature variations in the fluid start convection currents. The lower mantle in the Earth's mantle heats up due to heat from the core, which causes it to rise. The substance falls back as it cools, causing the convection current. The correct option is D.
Explanation:
Temperature differences in the fluid's area are what cause a convection current to be activated and the flow of a fluid to begin. The Earth's mantle is where this is most noticeable.
The lower mantle's temperature rises in this situation as a result of heat from the core. The density of the mantle material drops as it warms, causing it to rise.
As it rises and moves away from the heat source, however, it cools down, gets denser, and sinks back.This movement of rising and sinking due to temperature differences creates the convection current.The correct option is D.
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b. dissect.
c. diverge.
d. reverse.
Answer: Salivary Gland
Explanation:
The salivary gland in human being is exocrine gland which helps in the production of saliva through a system of ducts.
Human beings have three paired major ducts in salivary glands that secrete their secretions in the mouth by the help of duct.
The main type of enzyme secreted is alpha-amylase which helps in the breakdown of starch into glucose and maltose.
b. A blastocyst implants into the uterine wall.
c. A sperm fertilizes an egg to form a zygote.
d. A zygote undergoes mitosis.