Blood is composed of ___________.
plasma and red blood cells
plasma and formed elements
red and white blood cells
red blood cells, white blood cells and platelets
Thick muscular walls are present in ___________.
arteries
arterioles
veins
venules
The liquid portion of the blood is called _______
water
plasma
serum
sap
Stomata are present on the __________ of the leaves.
upper surface only
lower surface only
mostly upper surface
mostly lower surface
The colour of blood in the arteries is _________
bright red
dark red
blue
black
Deoxygenated blood is carried by _____________.
pulmonary artery
hepatic vein
renal vein
all of the above
The double membraned structure surrounding the heart is called _____________.
plasmalemma
pleural membrane
tonoplast
pericardium
Stomata open and close due to _____________.
presence of valves
hormonal control
turgor pressure of guard cells
concentration gradient of the gases
The cells that are full of water and rigid are called ________.
support cells
flaccid
turgid
none of the above
The ascent of sap in plants takes place due to __________.
root pressure
transpiration pull
both a and b
osmosis
