Which of the following statements are correct with reference to evolution?

(A) About 500 mya invertabrates were formed.

(B) Jawless fish evolved around 350 mya.

(C) About 400 mya sea weeds existed.

(D) About 100 mya dinosaurs suddenly disappeared.

Choose the correct answer from the options given below:

(A) and (B) only

The correct answer is Option (1)- (A) and (B) only

About 2000 million years ago (mya) the first cellular forms of life appeared on earth. The mechanism of how non-cellular aggregates of giant macromolecules could evolve into cells with membranous envelop is not known. Some of these cells had the ability to release O2. The reaction could have been similar to the light reaction in photosynthesis where water is split with the help of solar energy captured and channelised by appropriate light harvesting pigments. Slowly single-celled organisms became multi-cellular life forms.

By the time of 500 mya, invertebrates were formed and active. Jawless fish probably evolved around 350 mya. Sea weeds and few plants existed probably around 320 mya. We are told that the first organisms that invaded land were plants. They were widespread on land when animals invaded land. Fish with stout and strong fins could move on land and go back to water. This was about 350 mya. 

The land reptiles were, of course, the dinosaurs. The biggest of them, i.e., Tyrannosaurus rex was about 20 feet in height and had huge fearsome dagger like teeth. About 65 mya, the dinosaurs suddenly disappeared from the earth.  Some say climatic changes killed them. Some say most of them evolved into birds. The truth may live in between.