Cells contain a certain structure that acts as a gatekeeper in order to maintain homeostasis. This gatekeeper controls what is able to enter and exit the cell. Plant cells produce oxygen as a waste product. What cell structure allows this oxygen to pass into the environment?
A.
chloroplast
B.
vacuole
C.
endoplasmic reticulum
D.
cell membrane .
D. cell membrane
In the diagram below, structure A is labeled in two different types of cells. Which statement gives the best description of structure A?
A.
It helps regulate what enters and exits both cells.
B.
It helps absorb sunlight for both cells.
C.
It converts chemical energy into usable energy for both cells.
D.
It contains the DNA for both cells.
A. It helps regulate what enters and exits both cells.
The digestive system includes groups of tissues that absorb nutrients from food that has already been broken down. What is the best way to classify this group of tissues?
A.
an organelle
B.
an organ system
C.
an organ
D.
an individual organism
B. an organ system
The diagram shows a plant cell.
Which statement best describes the organelle labeled X?
A.
The ribosome creates proteins for the cell.
B.
The mitochondrion creates energy for the cell.
C.
The nucleus stores most of the genetic information for the cell.
D.
The nucleus controls everything that enters and exits the cell.
A. The ribosome creates proteins for the cell.
Michael almost gets into an accident in his car. How does his organ systems respond to this event?
A.
All of his organ systems stop working.
B.
His heart beats faster and his breathing rate increases.
C.
His respiration rate slows down.
D.
All of his neurons become paralyzed for ten seconds.
B. His heart beats faster and his breathing rate increases.
Which biome has a permanently frozen layer of soil called permafrost?
A.
savanna
B.
grassland
C.
tundra
D.
taiga