Question

Choose the correct answers from the alternative given.
Which of the following major advances was achieved by members of phylum Protista?
A. Multicellularity
B. Autotrophy
C. Sexuality
D. Both (a) and (b)

Answer 1

All prokaryotic organisms have been grouped under Kingdom Monera and unicellular eukaryotic organisms have been assigned to Kingdom Protista. They have a wide variety of food choices - photosynthetic, saprophytic, parasitic, holozoic or ingestive, etc.

Complete answer:
In Phylum Protista both asexual and sexual mode of reproduction is present.
Characteristics of kingdom Protista - Its members are unicellular and colonial eukaryotes. Most of them are aquatic and form plankton. The members of kingdom Protista are eukaryotic and eukaryotic cell body contains cell-bound cell organelles such as the nucleus, mitochondria, endoplasmic reticulum and the Golgi complex and others.
Based on the nutrition protists are divided into:
1. Autotrophic or photosynthetic organisms
-Dinoflagellates
-Diatoms
-Euglenoids

2. Consumer-Decomposer organisms
-Cellular slime mould
-Acellular slime mould

3. Protozoans
-Zooflagellates
-Sarcodines
-Ciliates

In Protista both sexual and asexual reproduction occurs. Members of kingdom Protista mostly live in aquatic habitats. Cellular organization consists of two types of envelopes. In addition to the plasma membrane, an inner membrane appears around certain organelles. Genetic material is organized in the form of a true nucleus. DNA is bound to histone proteins. Phylum Protista includes unicellular organisms so option (A) is correct. Some of the members of Protists are autotrophic but autotroph is also seen in members of Monera. Sexuality originates from protists and involves two processes: meiosis and fertilization.

Hence, the correct answer is option (D).

Additional information:
German biologist Ernst Haeckel offered a three-kingdom system (Protista, Plantae and Animalia) in his book Generelle Morphologie der Organismen. In the third kingdom Protista, he groups all unicellular organisms that act as intermediate between plants and animals. Herbert Copeland (1956) proposed the formation of a fourth kingdom, initially called Mycota but later Monera, which includes prokaryotes such as bacteria and blue-green algae .

Note: Dinoflagellates are not eukaryotes, they are mesokaryotic. Both sexual and asexual reproduction present. But there is no embryonic stage. In protista both sexual and asexual reproduction occurs also they are multicellular organisms.