Blood fails to clot in the absence of __________.
magnesium
calcium
sulphur
potassium
The main cells present in lymph are ___________.
red blood cells
platelets
lymphocytes
monocytes
__________ carries oxygenated blood.
pulmonary artery
hepatic portal vein
pulmonary vein
all of the above
Human circulatory system is called double circulation because of ___________
systemic and hepatic portal system
hepatic portal and pulmonary system
systemic and pulmonary circulation
systemic, hepatic and pulmonary circulation
The roots absorb water through _______________.
epidermal hairs
root hairs
root xylem
root phloem
The colour of blood in the arteries is _________
bright red
dark red
blue
black
Thick muscular walls are present in ___________.
arteries
arterioles
veins
venules
The double membraned structure surrounding the heart is called _____________.
plasmalemma
pleural membrane
tonoplast
pericardium
Pulse beat is measured in _____________
nerve
artery
vein
heart
Transpiration takes place from ________________.
all parts of the plant
roots
only the aerial parts
stem