Answer: The circulatory and digestive systems
Enzymes are catalysts that can be used more than once. If a substance needs to get broken down then it can use the corresponding enzyme to attach itself and break it down into simpler substances. After this is gone, the next substance might come up and attach itself to the enzyme like a lock-and-key model.
Therefore the answer is A) Enzymes accelerate chemical reactions without getting used up in the process.
In ocean acidification, dissolving co2 gas increases the ph of the ocean
Answer: B) ferns
Algae, liverworts and moss are examples of plants with no
real stems, leaves or roots and are also known as nonvascular plants. Plants
with true roots are known as vascular plants. Vascular plants have real roots, stems and leaves and contain vascular tissues.
Because comets are darker colored so they need light to shine on them to be seen in the dark skies of space.