<u>ANSWER:</u>
The correct order is- Zygote, Blastula, Gastrula, Fetus.
<u>EXPLANATION:</u>
- The embryo develops from the zygote which is formed when the gametes fuse in the process of "fertilization".
- The zygote undergoes cell division to form blastula which is a "ball of cells".
- Gastrula leads to the rearrangement of cells of the blastula into three layers that differentiate into different systems of organ.
- The last stage is the fetus which then develops into a baby.
The seeds are enclosed because it's the plants way of protecting them.
Hydrogen bonds exists between the DNA strand and its complementary strand such that; there are two hydrogen bonds between every A and T, and three between every C and G.
Therefore; in this case there will be (2 ×3 ) +(3×3) = 15 hydrogen bonds for the above strand. this is because Adenine binds to Thyamine with two bonds (3 pairs) and Guanine binds to Cytosine with three bonds (3 pairs).
