Xylem tissue that should help you out
Answer: The lock-and-key mechanism is usually associated with the complementary shapes of an enzyme with a single substrate wherein the lock that is being referred to is the enzyme and the substrate is the key. One right sized substrate (key) fits into the active site (key hole) of the enzyme (lock).
PH is a measure of how acidic something is
Explanation:
personal recount is a personal moment that you have experienced.
a factual recount is when it's a moment that the writer hasn't experienced but has seen or thinks it's interesting to write about.
