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

Explanation:

1. A population is a group of individuals of the same species living in the same place at the same time.
2. Westerlies blow from the subtropical high - pressure belts towards the poles.
3. In a P - N junction diode, the number of electrons and holes is not equal. In an n - type region, there are more electrons and in a p - type region, there are more holes.
4. The correct sequence of vertebrae in a mammal is cervical, thoracic, lumbar, caudal.
5. Lysosomes are present in animal cells only. Mitochondria, Golgi bodies and ribosomes are present in both plant and animal cells.
6. Loss of appetite and poor growth in humans are due to zinc deficiency.
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 leads to global warming. Bush burning increases the greenhouse effect as it releases carbon - dioxide and other greenhouse gases. So statements I and II are correct.

Answer:

1. A
2. A
3. D
4. D
5. B
6. D
7. B
8. C