Biology Questions

Nostoc is a prokaryote. Prokaryotic cells lack membrane bound organelles and well organized nucleus, that is nuclear envelope is absent in these cells.

The nuclear envelope, also known as the nuclear membrane, a bilayer membranes which surrounds the nucleus, and in eukaryotic cells it encases the genetic material.

Here from the above options, Algae is an Autotroph.

Autotrophs : 

An Autotroph is also called as Producer, is an organism that produces complex organic compounds from simple substances present in its surroundings, generally using energy from light or inorganic chemical reactions.

The absence of a nucleus is an adaptation of the red blood cell for its role. It allows the red bloodcell to contain more haemoglobin and, therefore, carry more oxygen moleculesLike red cells, platelets (thrombocytes) have no nucleus.Monocytes have a small spherical nucleus and has abundant dark staining condensed chromatin.There are 5 organelles found in a root hair cell. They are the: nucleus, cytoplasm, cell membrane, cell wall and vacuole.