Vascular bundles in monocotyledons are considered
closed because:

When you hold your breath, which of the following
gas changes in blood would first lead to the urge to
breathe?

Blood pressure in the mammalian aorta is
maximum during :

Which is the most common mechanism of genetic
variation in the population of sexually reproducing
organism?

Erythropoiesis starts in :

In an ecosystem the rate of production of organic
matter during photosynthesis is termed as: