The pigment that is the primary electron donor in photosystem I is: MCQ with Answer and Explanation

Explanation:
Nostoc is a cyanobacterium (blue-green alga) that fixes atmospheric nitrogen and is used as a biofertilizer in rice paddies. Anabaena azollae with Azolla is also common. Rhizobium is bacterial biofertilizer for legumes, Azospirillum is a free-living nitrogen-fixing bacterium. Trichoderma is a fungal biocontrol agent. BGA biofertilizers increase organic nitrogen in soil.

Explanation:
The platypus is a monotreme (egg-laying mammal) with a duck-like beak, no teeth, and webbed feet. Bats and whales are placental mammals, kangaroo is a marsupial. Platypus is found in Australia.

Explanation:
The skeletal system, composed of bones and cartilage, provides structural support for the body, protects vital internal organs (like the brain and heart), and serves as a site for muscle attachment. The muscular system, consisting of skeletal, smooth, and cardiac muscles, contracts to produce movement of the body and internal organs. The endocrine system comprises glands that secrete hormones directly into the bloodstream to regulate various physiological processes. All statements are correct.