Heart wood differs from sapwood in
1. Absence of vessels and parenchyma
2. Having dead and non-conducting elements
3. Being susceptible to pests and pathogens
4. Presence of rays and fibres

Which of the statements given below is not true about the formation of annual rings in trees?
1. Annual rings are not prominent in the trees of temperate regions.
2. Annual rings are a combination of spring wood and autumn wood produced in a year.
3. Differential activity of cambium causes light and dark bands of tissue - early and late wood respectively.
4. Activity of cambium depends upon the variation in climate.