State one importance of photoperiod in agriculture.

Poultry fowl are susceptible to the following pathogens:

$(a)$ What is lactation period? Name two breeds of cattle which are selected for their long lactation period. Why are they crossed with local breeds?
$(b)$ What are roughage and concentrates?

Farmer $X$ planted Soyabean $+$ Maize $+$ Cowpeas in the same field simultaneously in a set row pattern. Farmer $Y$ planted cereal crop in one season and leguminous plants in the next season on the same piece of land in pre-planned succession. $(a)$ Name the cropping patterns used by farmers $X$ and $Y$. $(b)$ State two advantages of the different cropping patterns followed by farmers $X$ and $Y$ respectively.

Why is there a need for varietal improvement?

$(a)$ Distinguish between macronutrients and micronutrients on the basis of $(i)$ their functions and $(ii)$ amount required by plants. $(b)$ Classify the following elements as macro or micronutrients in plants: $(i)$ Nitrogen,$(ii)$ Zinc,$(iii)$ Copper,$(iv)$ Potassium. $(c)$ In what way is the deficiency of these nutrients harmful to crops?