What happens if the egg is not fertilized?

$A$ feature of reproduction that is common to $Amoeba$,$Spirogyra$ and $Yeast$ is that

Which among the following statements are true for sexual reproduction in flowering plants?

Some plants do not produce seeds. For such plants,parts like roots,stem,and leaves are used to develop into new plants.
$(a)$ Identify the process.
$(b)$ Which type of reproduction is it—sexual or asexual? Answer with reason.
$(c)$ Give any two examples of this process.

Differentiate between the following:
$(a)$ Placenta and uterus
$(b)$ Unisexual and bisexual flowers
$(c)$ Fertilization and germination

Differentiate between pollen grain and ovule.