Down;s syndrome is also known as trisomy 21 because it is caused by an additional copy of chromosome 21. The correct answer is the third one: 21st.
Answer:C,D,E
Explanation:I did the USA test prep
Since they have no predators the zebra mussel population will grow rapidly. Whatever the zebra mussels consume will have a major decrease in population since there are so many zebra mussels.
A mutation is a new element added to the genetic buildup of an organism. this leads to new abilities that makes that organism adapt to different things, this is passed down through the organisms descendants which will help them get through situations other organisms can't, thus helping the entire species evolve.
Answer:
A
Explanation:
I EAT CHEESE AND I TOOK THE TEST
