100. In life history evolution there is generally a tradeoff between the size and number of offsprings produced.
     Some conditions are listed below:
     A. Scarcity of food during the early stages of life
     B. Provision of parental care
     C. High mortality during early stages of life
     D. Predator’s preference for large sized prey
     What are the above two conditions that would favour the production of a small number of large-sized offspring?
     (1) B and C (2) Band D
     (3) A and B (4) A and C

Introduction

A central concept in life history evolution is the trade-off between the size and number of offspring an organism produces. Environmental pressures and ecological factors shape whether a species invests in many small offspring or a few large ones. Two key conditions—parental care and predator preference for large prey—play a major role in favoring the production of fewer, larger offspring. Let’s explore why these factors are so influential.

The Size–Number Trade-Off in Offspring

Organisms have limited resources to allocate to reproduction. Investing more in each offspring (making them larger) usually means producing fewer overall, while producing many small offspring often comes at the expense of individual survival chances. The best strategy depends on the environment and the specific challenges offspring face.

Which Conditions Favor Fewer, Larger Offspring?

Let’s examine the four conditions:

• A. Scarcity of food during the early stages of life

• B. Provision of parental care

• C. High mortality during early stages of life

• D. Predator’s preference for large sized prey

Parental Care (B)

Parental care increases the survival, growth, and quality of offspring, allowing parents to invest more resources into fewer young and ensure their success. When parents provide care, they can afford to produce fewer, larger offspring because each has a higher chance of surviving to adulthood. This is a classic driver of the evolution of larger offspring size and smaller clutch size.

Predator’s Preference for Large Prey (D)

If predators prefer large-sized prey (offspring), producing a small number of large offspring can be risky. However, in some ecological contexts, parents may compensate for this by increasing care, camouflage, or defense, still favoring fewer, larger offspring if it increases the odds of survival despite predation pressure.

Scarcity of Food (A) and High Early Mortality (C)

Scarcity of food can sometimes favor larger offspring, as they are better able to survive periods of starvation. High early mortality, on the other hand, often leads to the production of many small offspring (r-strategy), betting on numbers for survival rather than size.

Which Pair Best Fits?

The two conditions that most strongly favor the evolution of a small number of large offspring are:

B. Provision of parental care
D. Predator’s preference for large sized prey

• Parental care allows for greater investment per offspring, increasing survival and favoring larger size.

• Predator preference for large prey can select for strategies that minimize predation risk, sometimes by producing fewer, more defensible or better-cared-for offspring.

Conclusion

The two conditions that favor the production of a small number of large-sized offspring are:

(2) B and D — Provision of parental care and predator’s preference for large sized prey.