The movement of water through the apoplast pathway does NOT cross which layer in the root? MCQ with Answer and Explanation

Explanation:
Pellagra is caused by a severe deficiency of Vitamin B3 (Niacin) or its precursor, the amino acid tryptophan. The classic symptoms are the '4 Ds': dermatitis (symmetrical, pigmented rash on sun-exposed skin), diarrhea, dementia (neurological symptoms), and eventually death if untreated. It is historically associated with diets heavily reliant on untreated corn (maize), which has low bioavailable niacin and tryptophan.

Explanation:
Cacti, xerophytes, have spiny leaves to minimize surface area and transpiration, conserving water. Thus, R correctly explains A.

Explanation:
Commensalism (+/0) involves one species benefiting and the other neither harmed nor helped. Example: barnacles on a whale, or cattle egrets eating insects stirred by cattle. Mutualism benefits both (+/+), parasitism benefits one at expense of other (+/-), predation (+/-) involves killing. The distinction is based on the net effect.