In the photosynthetic purple bacteria, the phototactic movements shown by them seem to be due to light absorbed by

Which hormone is found in the gaseous form?

A. Abscisic acid

B. Ethylene

C. Gibberellins

D. Auxins

In the Tetrameles - Stereospermum - Cedrela formation which of the following associations is recognised?

A. Cinnamomum - Amoora association

B. Bischofia - Dillenia association

C. Shorea - Lagerstroemia association

D. Mesua - Michelia association

Which of the following react with haemoglobin, forming methemoglobin which will not take up oxygen?

A. Nitrates

B. Nitrites

C. Carbides

D. Oxides

Internally, hydathode shows a group of loosely arranged parenchymatous cells called as

A. Epiderm

B. Epithelium

C. Ampithecium

D. Epithem