Which is produced when an egg cell is fertilized by a sperm cell?
a. larva
b. an embryo
c. a spore
d. pollen

The correct answer is B.

Formation of an embryo begins  when the sperm cell meets an egg. When they meet, a zygote  is first formed. A zygote is a single diploid cell created when two haploid cells merge.

The zygote begins to divide , and when this division starts, the zygote turns into an embryo. So an embryo is an organism that is at the early stages of development and which is not able to survive on its own.

The term embryo is used only  to refer to eukaryotes or organisms that are multi cellular.

here is the answer

water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. weathering is the breaking down or dissolving of rocks and minerals on earths surface. once a rock has been broken down, a process called erosion transports the bits of rock and minerals away.