Which definition is the best for “semipermeable membrane”? It is a barrier that prevents materials from moving from one side to the other.

It is a barrier that allows materials to move freely from one side to the other.

It is a barrier with tiny openings that let some, but not all, materials pass through.

It is a barrier that helps materials move from one side to the other.

Blood has traveled from the heart to the toes. which describes the next step of the circulation process?

How does natural selection change thephenotypes within a population over time?

Which of the following statements is most likely correct about a rock belonging to the jurassic age and a rock belonging to the cambrian age? options: 1) they have identical fossils of organisms that have evolved over time. 2) both have animal fossils preserved in them due to weathering and erosion. 3) they contain different fossils because life on earth has changed through time. 4) the fossils in them were formed on the surface of earth due to exposure to sunlight.