what stage mitotic division is represented in the diagram of the cell illustrated above
پاسخ دهید
(A)
Prophase
2
This stage of mitosis is characterized by the
پاسخ دهید
(E)
condensation of chromosomes and formation of spindles
3
The ability of organisms to maintain a constant internal environment is known as
پاسخ دهید
(E)
homeostasis
4
Double fertilization is said to occur in flowering pants because?
پاسخ دهید
(D)
one embryo and endosperm nucleus are formed
5
THe bicuspid valve is located between the
پاسخ دهید
(A)
left auricle and left ventricle
6
The pulmonary artery carries
پاسخ دهید
(A)
deoxygenated blood from the right ventricles to the lungs
7
Which of the following blood components has the greatest affinity for oxygen and carbondioxide?
پاسخ دهید
(D)
Erythrocytes
8
The thoracic cavity is separated from the abdominal cavity by a sheet of muscle called
پاسخ دهید
(C)
diaphragm
9
Deamination is the process during which
پاسخ دهید
(A)
excess amino acid is broken down into ammonia and keto acid
10
Which of the following statements on urine production is not correct?
پاسخ دهید
(E)
in the presence of antidiuretic hormone dilute urine is produced
11
The pigment in the malphigian layer responsible for skin colouration is known as
پاسخ دهید
(E)
melanin
12
Co-ordination is achieved in the body of mammals through the action of the
پاسخ دهید
(A)
endocrine and nervous systems
13
Which of the following statements is correct of hormones? Hormones are
پاسخ دهید
(B)
secreted directly into the blood streem
14
The pituitary is called 'master gland' because
پاسخ دهید
(C)
its secretion controls the other glands
15
Auxins are produced in the
پاسخ دهید
(D)
apical regions of roots and shoots
16
The brain and the spinal cord make up the
پاسخ دهید
(C)
central nervous system
17
Which of the following specialized structures are stimulated by touch, pressure, pain, heat and cold?
پاسخ دهید
(A)
Receptors
18
Which of the following is not correct about a fruit? lt
پاسخ دهید
(E)
possesses only one scar.
19
Which structure in the maize grain stores food?
پاسخ دهید
(E)
Endosperm.
20
Which of the following does not occur during photosynthesis?
پاسخ دهید
(B)
Carbondioxide is evolved
21
Even though some flowering plants contain accessory pigments which give them colours they still contain
the pigment
پاسخ دهید
(B)
chlorophyll
22
Which of the following is not regarded as a micro-nutrient or trace element for plant growth?
پاسخ دهید
(A)
Phosphorus
23
In a water culture experiment a plant showed poor growth and yellowing of the leaves. These symptoms
were probably due to the absence of
پاسخ دهید
(C)
iron
24
The relationship between a herbivore and the bacteria which live in its caecum is known as
پاسخ دهید
(B)
symbiosis
25
Autotropic nutrition may be defined in terms of food obtained
پاسخ دهید
(D)
by synthesizing simple substances using energy from an external source
26
Which of the following is not classified as a terrestrial habitat?
پاسخ دهید
(D)
Littoral zone
27
Which of the following does not contribute to the biomass in an ecosystem?
پاسخ دهید
(B)
Food chains
28
Which of the following is not a characteristic feature of tropical rain-forest habitat?
پاسخ دهید
(B)
Fewer canopy strata than the savannah
29
Which of the following factors is not associated with aquatic habitat?
پاسخ دهید
(C)
Humidity
30
Terrestrial organisms which are capable of maintaining their body temperature constant within fairly close
limits are referred to as
پاسخ دهید
(B)
homotherms
31
Which of the following statements is not true of a climax vegetation? It
پاسخ دهید
(C)
eliminates competition
32
The causative organism of sleeping sickness is the?
پاسخ دهید
(A)
Trypanosome
33
Which of the following are not causative organisms of plant diseases?
پاسخ دهید
(E)
Cercariae
34
The vector of the malarial parasite is the
پاسخ دهید
(D)
female Anopheles
35
A constituent of the exhaust gases of motor vehicles which causes serious air pollution is
پاسخ دهید
(C)
carbon monoxide
36
Which of the following steps would not be taken to protect or conserve fishing grounds from over-exploitation?
پاسخ دهید
(A)
. Use of nets with all sizes of mesh
37
Which of the following .is not part of the objectives of conservation of natural resources?
پاسخ دهید
(A)
To eliminate wild animals in order to enable other plants and animals survive
38
During blood transfusion, agglutination may occur as a result of the reaction between
پاسخ دهید
(B)
contrasting antigens and antibodies
39
Which of the following major ideas were proved by Gregor Mendel?
پاسخ دهید
(E)
Characteristics of an organism are controlled by genes occurring in pairs
40
Assuming that ‘A’ is gene for normal skin and it is dominant, while ‘a’ is gene for albinism and it is recessive,
what is the likely genotype of a couple which had 50% normal and 50% albinos?
پاسخ دهید
(D)
Aa, aa
41
Which of the following is not a constituent of DNA?
پاسخ دهید
(E)
Uracil.
42
Which of the following best describes the homologous chromosomes? They are
پاسخ دهید
(B)
two identical chromosomes from each parent
43
The haploid number of chromosomes in man is
پاسخ دهید
(E)
23
44
If a cross is made between a pure-breeding red flowered plant and a pure-breeding white flowered plant
where R is dominant for red flower and r is recessive for white, the most likely result of F generation will be
پاسخ دهید
(B)
all red flowers
45
A man with blood group A (TAP) married a woman with blood group O (pp). Which of the following is the
probable ratio of the blood groups of the offspring?
پاسخ دهید
(A)
1:1
46
Increasing specialization of structure and function among animals of the same class and order for survival in new and different environments is called
پاسخ دهید
(A)
adaptive radiation
47
When large numbers of organisms share limited space and resources the result is
پاسخ دهید
(E)
competition
48
The change in colour of the chameleon serves as a means of
پاسخ دهید
(C)
a camouflage from a predator
49
Species can be defined as the group of organisms that
پاسخ دهید
(C)
resemble each other and can interbreed freely
50
Which of the following is not true about gene mutation? It
