Select all of the answers that apply.

cyanobacteria are thought to have introduced oxygen into the early atmosphere. this was important because oxygen played a key role in

the evolution of eukaryotic organisms
the water cycle
creating an ozone layer to shield life from uv rays
the greenhouse effect
recycling of essential materials

creating an ozone layer to shield life from UV rays

Cynobacteria or blue green algae is the strain of bacteria, which was able to produce oxygen in the primitive earth as a result of photosynthesis. The abundance of oxygen in the atmosphere formed the ozone layer in the upper atmospheric layers, these layers are protective enough to provide a shield against the harmful UV radiations incident on earth coming from the sun.

the evolution of eukaryotic organisms

creating an ozone layer to shield life from UV rays

Explanation:

Cyanobacteria are the photosynthetic bacteria which increased in number in the pre-Cambrian period and produced a very high amount of oxygen.

This oxygen in the atmosphere mainly in the ionosphere reacted to form the ozone layer which protects against UV rays.

The organisms living during that period were mostly anaerobic that is were using other substrate molecules for respiration other than oxygen but due to increasing in concentration of oxygen about 75 % species became extinct and about 25% evolved to form the first animals or eukaryotes on Earth.

Thus, the selected options are correct.

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

hope it !

answer: angiosperms

dicots

angiosperms are highly evolved plants, they produce seeds which are enclosed within in a carple. these are the largest group of plants on earth. they include trees, shrubs, herbs and small flowering plants. angiosperms exhibit a flowering stage in their life cycle. the flower serves the function of reproduction and fruit formation in majority of angiosperms. dicot is the term used to describe flowering plants that have two seed leaves. dicots are plants which develop seeds which split into two parts called cotyledons. each cotyledon contains one embryo.

here, a small purple flower development indicates that the plant belongs to angiosperms and having two embryonic leaves indicates it belongs to dicots.