Question

1. members of the same species living at the same place at the same time make a

a. population
b. ecosystem
c. community
d. trophic level

1. the westerlies are winds that blow

a. from the poles.
b. towards the poles.
c. towards the equator.
d. from the equator.

1. the p - n junction diode has

a. equal number of holes and electrons.
b. no holes.
c. no electrons.
d. more electrons than holes.

1. the correct sequence of the arrangement of vertebrae in a mammal is

a. thoracic, caudal, lumbar, cervical.
b. cervical, lumbar, thoracic, caudal.
c. thoracic, cervical, lumbar, caudal.
d. cervical, thoracic, lumbar, caudal.

1. which of the following structures is present in animal cells only?

a. mitochondrion
b. lysosomes
c. golgi body
d. ribosome

1. loss of appetite and poor growth in humans are due to the deficiency of

a. sodium.
b. iodine.
c. copper.
d. zinc.

1. nucleons refer to the sum of

a. electrons and neutrons in an atom.
b. protons and neutrons in an atom.
c. protons and electrons in an atom.
d. electrons and molecules in an atom.

1. which of the following statements are correct?

i. green house effect can be reduced by afforestation.
ii. one effect of ozone layer depletion is global warming.
iii. green house effect is reduced by bush burning.
a. ii and iii only
b. i and iii only
c. i and ii only
d. i, ii and iii
25/sc517105/feb/wsc

Explanation:

1. A population is a group of individuals of the same species living in the same place at the same time.
2. Westerly winds blow from the subtropical high - pressure belts towards the poles.
3. In a P - N junction diode, there are different numbers of holes and electrons depending on the doping, but not equal numbers.
4. The correct sequence of vertebrae in a mammal is cervical, thoracic, lumbar, caudal.
5. Lysosomes are more prominent in animal cells compared to plant cells. Mitochondria, Golgi body and ribosome are present in both plant and animal cells.
6. Zinc deficiency can lead to loss of appetite and poor growth in humans.
7. Nucleons refer to the sum of protons and neutrons in an atom.
8. Afforestation can reduce the greenhouse effect as plants absorb carbon dioxide. Ozone layer depletion is related to increased UV radiation and has an impact on climate including global warming. Bush burning releases carbon dioxide and other greenhouse gases, increasing the greenhouse effect.

Answer:

1. A
2. A
3. None of the above (the correct statement about P - N junction diode is more complex than these options)
4. D
5. B
6. D
7. B
8. C