The cell membrane of a cell is said to be semi-permeable because
it allows only large molecular substances to pass through it into the cell
it is actively involved in energy production in the cell
it actively allows all substances to pass through it by diffusion
it is actively selective in allowing substances pass through it
fatty acids are only the building blocks of the membrane
Correct answer is D
No explanation has been provided for this answer.
symbionts
omnivores
heterotrophs
autotrophs
carnivores
Correct answer is C
No explanation has been provided for this answer.
Higher organisms use a transport system and not diffusion only to distribute nutrients because
the ratio of their surface area to volume is small
metabolic waste products diffuse to the surface of the organisms
the rate at which nutrients and other substances diffuse increases
substances to be transported move shorter distances to reach the numerous cells
the internal structures of the organisms are in direct contact with the environment
Correct answer is A
No explanation has been provided for this answer.
Which of the following is not a tissue found in plants?
Epidermis
Phloem
Xylem
Dermis
Mesophyll
Correct answer is D
No explanation has been provided for this answer.
Which of the following pairs of tissues is responsible for strengthening the plant?
Phloem and Epidermis
Parenchyma and Cambium
Collenchyma and Sclerenchyma
Collenchyma and Cambium
Xylem and Cambium
Correct answer is C
Collenchyma cells have thin primary walls with some areas of secondary thickening. Collenchyma provides extra mechanical and structural support, particularly in regions of new growth.
Sclerenchyma cells have thick lignified secondary walls and often die when mature. Sclerenchyma provides the main structural support to a plant.