What is the coronavirus a] a fungal infection b]a viral infection c] the flu d] a bacterial infection

The table shows dates and appearance of index fossils. which rock layers can be dated most precisely? a) a layer containing both a fossil 4 and a fossil 3 b) a layer containing both a fossil 2 and a fossil 3 c) a layer containing both a fossil 1 and a fossil 4 d) a layer containing both a fossil 1 and a fossil 2

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Genetic disorders can result when sister chromatids fail to seperate properly. during what phase is this problem most likely to occur?