The variable '$r$' in population dynamics often signifies the intrinsic rate of increase or the per capita growth rate. A high '$r$' indicates rapid population growth, while a low or negative '$r$' suggests slow growth, stability, or population decline.
When a plant pathogen encounters 'resistance', it means its ability to reproduce and proliferate is significantly hampered. This could be due to host defenses, unfavorable environmental conditions, or other limiting factors. Consequently, the pathogen's rate of reproduction decreases.
Given that resistance impedes reproduction, the rate '$r$' must be significantly lower than what allows for rapid spread (i.e., less than '$r > 1$'). The range '$r = 0 - 1$' accurately reflects a scenario where the pathogen's reproductive capacity is severely limited or negative due to resistance, preventing significant population growth.
| LIST-I Chromosomal aberrations | LIST-II Chromosome number |
|---|---|
| A. Nullisomic | I. 2n + 1 |
| B. Monosomic | II. 2n + 2 |
| C. Trisomic | III. 2n - 2 |
| D. Tetrasomic | IV. 2n - 1 |
| LIST-I Scientist | LIST-II Discovery |
|---|---|
| A. Yule | I. Mitosis |
| B. Watson & Crick | II. Multiple factor hypothesis |
| C. Jacob & Monod | III. Double helical structure of DNA |
| D. Fleming | IV. Operon concept |
| List-I | List-II |
| Electronic Configuration | First Ionisation energy (kJ mol$^{-1}$) |
| (A). ns$^2$ | (I). 2100 |
| (B). ns$^2$np$^1$ | (II). 1400 |
| (C). ns$^2$np$^3$ | (III). 800 |
| (D). ns$^2$np$^6$ | (IV). 900 |
| List-I | List-II |
| Spectroscopy | Property |
| (A). Raman | (I). Polarizability |
| (B). FTIR | (II). Dipole Moment |
| (C). UV-Visible | (III). Absorbance |
| (D). NMR | (IV). Spin |