So planarians' regenerative ability are powerful cells called pluripotent stem cells, which make up one-fifth of their bodies and can grow into every new body part. I hope this helped if you need more info about this let me know
B. the recessive allele is masked in heterozygotes
Boron and Calcium..........
Answer:
<h2>B
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Explanation:
1. Amphibian's heart is three-chambered from which two are atria and only one is ventricle.
2. And there is two circulatory pathways having different routes.
3.There is mixing of oxygenated and deoxygenated blood in case of amphibians.
4. And in case of mammals there is no mixing of blood,, both the oxygenated and deoxygenated blood is completely separate.
5. Mammal's heart contain four chambers from which two are atria and two are ventricle, and they completely separate both the oxygenated and deoxygenated blood.
The first 3!!! Hope this helps