Which of the following statements about innate immunity is true?
it involves the activity of b and t cells.
innate immunity is present at birth. innate immunity involves specific recognition of microorganisms via a memory response.
the innate immune response does not have a mechanism for detecting invading microorganisms.
it is activated only in response to tissue damage or a signal from an infected cell.

Innate immunity is present at birth.

Explanation:

The immune system is divided into two categories such as innate immunity and adaptive immunity. The innate immunity is present in an individual during birth. It does not depend on prior contact with microorganisms or immunization. It is present at birth and changes throughout the life of the individual. There are different barriers of innate immunity such as skin, mucous, lysozymes (present in the tears). This type of response is rapid and not specific. It has no memory. The cells of innate immunity are the phagocytic cell, dendritic cells.

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 !