ASSIGNMER (b) Fig. 7.2 shows the total cross-sectional area of the blood vessels in the systemie
circulation. It also shows the changes that occur in blood pressure and the speed
(velocity) of blood in the different blood vessels.
6.
vena cava
Bora
issue huid
SS
29
3
4000
total Cross-
3000
sectionarea
of the blood
vessels./ama 2000
1000
0
pressure
mean blood
Pressure / Pa
speed of the
blood /cm 5-1
50
-40
valocity
16112109876543210
30
-20
10
0
aorta
arteriales
arteries capillaries
veins
vena cava
Fig. 7.2
(i) State the maximum mean blood pressure in the aorta.
13 kPa
[1]
(ii) Describe how mean blood pressure and speed of blood change with cross-
sectional area of blood vessels, as shown in Fig. 7.2.
blood pressure
NSSCO BIOLOGY - ASSIGNMENT 1 - 2021
24​

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.