Answer:
B, A fossil found in rocks from one time period
Explanation:
Fossils are used to determine the ages of rock layers. Index fossils are the most useful for this. Index fossils are of organisms that lived over a wide area. They lived for a fairly short period of time. An index fossil allows a scientist to determine the age of the rock it is in. Hope that this helps you :)
A. can cats learn to sit down on command
Answer:
Totipotent Stem Cells - They can differentiate into any type of human body cell or the placenta.
Example: Fertilized egg cells.
Pluripotent Stem Cells are from totipotent cells and can differentiate into any cell in the human body; however, not many are in the placenta.
Example: Blastocyst cells.
Multipotent Stem Cells - They can only differentiate into closely related cells.
Example: Blood stem cell
Unipotent Stem Cells - They can only produce their type of cell.
Example: Skin stem cells (which can only become a new skin stem cell).
Explanation:
Fetuses who were more active during the last trimester of the pregnancy became 2 year olds who were less fearful when interacting with an unfamiliar adult in a laboratory, and those with one year knew how to handle frustration better than those who were less active during the last trimester.
It also reabsorbs water found in the undigested food
