Which of the following is an example of sexual reproduction?
a pollen grain from one flower fertilizes another flower, resulting in the development of a seed.
a bacterium copies its dna and divides into two daughter cells in a process called binary fission.
a piece of a starfish is broken off and grows into a new starfish in a process called regeneration.
a yeast offspring grows out of the body of its parent in a process called budding.

Sexual reproduction is occurring in the following examples:

•A pollen grain from one flower fertilizes another flower, resulting in the development of a seed.

•A frog releases sperm over eggs that were laid by another frog, and these cells fuse together.

Explanation:

b

is correct hope this   also i learnd this in middle school

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.