The structure of dna is held together by?

A. purines pairing with pyridimines

B. hydrogen bonds between adenine and thymine

C. attraction between cytosine and guanine.

D. All of the above

In this activity, you will identify portals of entry and exit found in a human host. sort each item based on whether it represents a portal of entry, portal of exit, or both portal types.

Which of the following contains the greatest number of unipotent stem cells? A. 6-week-old embryo B. Blastocyst C. Adult D. 3-day-old embryo

True or false all animal cells have the same number of chromosomes

How does a cell maintain homeostasis?

1 Pterodactyl (reptile) 2. Bat (mammal) 3. Albatross (bird) Why are the wings considered analogous structures while bones in these forelimbs are considered homologous structures?

Why malarial concepts called hypothesis?

What would likely have happen to earth if no icy debris had arrived

What is an example of temporal isolation? A. flowers that bloom in different months B. birds that have different mating calls C. fruit flies that mate in different locations D. squirrels that have different fur colors

The leg amputation is likely to involve

Which of the following is an example of an emergent property? Sunlight is absorbed by pigments within plant leaves. The DNA backbone contains sugar groups and phosphate groups.