Answer:
a and b are most probable options
Explanation:
<span>Trophoblasts
Trophoblasts are cells that make up the external layer of a blastocyst, this is a major source of nutrient for a newly formed organism</span>
Answer:
Mutations:
When DNA changes then it is called mutations.In then others words when DNA is damaged or we can say that when it changed then it changes the genetic genes and this changes in genetic gene is called mutations.
The types of mutations
1.Non sense mutations
2. Missense mutations
It can affect the genetic order .This is called genetic disorder.
Letter a i guess probably
