Which organism possesses the highest number of chromosomes?

Which of the following statement$(s)$ is/are correct for cleistogamous flowers?
$(a)$ They have exposed anthers and stigma
$(b)$ They produce assured seed set
$(c)$ They need pollinators for pollination
$(d)$ Variations in traits are not seen in next generation

Gametes are generally ...... .

An $8$-nucleate embryo sac is $..........$.

The chromosomal number in a cell of a flowering plant is:

The pollen viability period of rice and pea respectively,is