NEET Biology Organisms and Populations MCQs Set 09

Answer: (b) Large, thin leaves with many exposed stomata

Explanation:
1. Xerophytes reduce transpiration with thick cuticle, sunken stomata and CAM, not with large thin leaves.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (d) increasing red blood cell production and breathing rate

Explanation:
1. RBC production and breathing rate rise while the binding affinity of haemoglobin for oxygen falls, releasing more oxygen to tissues.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (a) population

Explanation:
1. Such a group, also called a deme, forms a population.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (c) there is a large difference in the size of individuals

Explanation:
1. A huge tree and a small herb cannot be compared by count, so biomass is used.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (d) Counting pugmarks and faecal pellets

Explanation:
1. Indirect counts use signs such as pugmarks and faecal pellets.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (a) pre-reproductive group is the largest

Explanation:
1. A broad base indicates many young individuals, so the population is expanding.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (c) pre-reproductive and reproductive groups are almost equal in size

Explanation:
1. A bell-shaped pyramid shows nearly equal numbers in the younger age groups.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (b) Nt+1 = Nt + (B + I) - (D + E)

Explanation:
1. Natality (B) and immigration (I) add individuals; mortality (D) and emigration (E) remove them.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (a) natality + immigration = mortality + emigration

Explanation:
1. Equal gains and losses leave the size unchanged.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (c) intrinsic rate of natural increase

Explanation:
1. r = b - d, the difference between per capita birth and death rates.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (b) Nt = N0 e^(rt)

Explanation:
1. Integrating dN/dt = rN gives Nt = N0 e^(rt), with e = 2.718.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (d) J-shaped curve

Explanation:
1. With unlimited resources the population keeps multiplying and the curve rises steeply (J-shaped).

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (c) environmental resistance

Explanation:
1. It decreases as N approaches K and slows growth.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (a) carrying capacity

Explanation:
1. This is represented by K in the logistic equation.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (d) Logistic (sigmoid) curve

Explanation:
1. Resources are limited in nature, so growth finally levels off at K.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (b) zero

Explanation:
1. The bracket (1 - N/K) becomes zero, so growth stops.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (b) mutualism

Explanation:
1. Obligatory +, + association is mutualism (for example lichens); optional +, + association is proto-cooperation.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (d) Cattle egret and grazing cattle

Explanation:
1. Egrets benefit from insects disturbed by cattle while the cattle are unaffected.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (a) sexual deceit

Explanation:
1. One petal resembles a female bee; male bees pseudocopulate and transfer pollen.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.

Answer: (c) two closely related species competing for the same limited resources cannot coexist indefinitely

Explanation:
1. The competitively inferior species is eventually eliminated if resources are limiting.

Teacher's Note:
1. Read the question carefully and relate it to the core concept of the chapter.
2. Note the key terms in the options, since examiners use close alternatives.