Selectively permeable (or semi permeable) means where for example a membrane can choose what material can pass through while others cannot. They control the in and out of materials.
This is because the membrane has tiny spaces, where only smaller molecules can pass through, other larger ones cannot.
B. group of the same species that live together.
By multiplying the rate constant by the substrate concentration (amount) or by determining reaction velocity (V).
A. it has uracil
We know the sequence is RNA because it contains uracil.
