Q: Content is accurate, error-free and unbiased

Errors/omissions noted:
The claim (on p.11) that "How did life on Earth originate?" cannot be answered because "NO evidence can be gathered to support or refute it" is incorrect. A variety of hypotheses about tat specific question exist and are subject to the collection of evidence that support or refute each.
The discussion of astrology in the 'Pseudoscience' section is fine, but in this context it would seem that medically-applicable pseudoscience examples (homeopathy comes to mind) would be more useful.
Figure 2.2.4 needs to specify Onion SKIN cells; cells will appear quite different elsewhere in the plant.
"How Well Enzymes Work" section does not actually explain how WELL enzymes work. Either a title change ("How enzymes work") or a content change (quantification of their effectiveness, e.g. of increased rates of reactions) should be done for clarity.
Typo in image caption: the first figure in section 3.13 is numbered 3.13.2 instead of 3.13.1.
Osmosis section: "Like other molecules, water moves from an area of higher concentration to an area of lower concentration"... "concentration" is not specified as "concentration of water" or "its concentration", and thus the definition does not make sense. This imprecision reappears throughout the text - should be in reference to "its concentration" or "their concentration", not just any concentration.
References in section 4.8 include one for Ouabain, which does not appear to be included anywhere in the text?
Cellular respiration equation at start of section 4.10 is missing a + sign between the products.
The bottom of Figure 4.10.2 is cut off in the print version.
The bottom of Table 7.4.2 is cut off in the print version.
Reference for Figure 11.3.12 is missing a space between "Wikipedia" and "on".
The "Feature: Reliable Sources" in section 11.4 includes no information about what constitutes a 'reliable resources.'
Section 12.2 first paragraph uses the term 'flex' incorrectly in the context of a postsecondary A&P course. Muscles CONTRACT to flex a joint, muscles themselves do not flex.
Section 12.5: "Aerobic exerciseis any physical activity..." needs a space added to read "Aerobic exercise is any physical activity...".
Table 15.3.1 needs to pluralize "Reactants and Products".
Figure 15.4.6 should not be included without a normal reference image and additional labels to indicate visible structures. As it is, it makes no sense to show this image to an introductory student.
Section 16.2 "Skin" description of functions; sweating does not effectively remove excess water or salts; kidney malfunction cannot be made up for by sweating through the skin. More careful wording should be used here, e.g. removal of some water or salts, loss of water or salts, excessive loss of water or salts, or the like.
Figure 16.5.5 lacks labels and orientation indication.
Figure 18.2.4 incorrectly identifies the abdominopelvic cavity (or 'pelvic cavity') as the abdominal cavity.

Broader issues about content:
Includes many references to Wikipedia pages, which are not static and thus cannot be reliably verified. Wikipedia links may be useful as reference for "for more information, you may wish to read...", but should not be used as references for factual information.
Some Chapter summaries are excessively long for summaries. It is unclear what function is served by having such large blocks of point-form text. Sections 3.13, 4.14, and 5.18 stand out as especially absurd.

Content Accuracy Rating: 4 out of 5

Q: Content is up-to-date, but not in a way that will quickly make the text obsolete within a short period of time. The text is written and/or arranged in such a way that necessary updates will be relatively easy and straightforward to implement

Links to websites that may change over time are fine for citations of sources of images, but should not be used as references for factual information. Some youtube and wikipedia links include extraneous characters at the end of the links (e.g. "&feature=youtu.be"), and should be checked to ensure the simplest possible usable form of the link is used.
It would be useful to include QR codes for all weblinks, so they remain accessible in the print version. In several places links appear in the print version alongside no image at all, as do links to interactive/media elements.

Relevance Rating: 4 out of 5

Q: The text is written in lucid, accessible prose, and provides adequate context for any jargon/technical terminology used

I noticed no major issues with the prose style.

Clarity Rating: 5 out of 5

Q: The text is internally consistent in terms of terminology and framework

Overall yes the text is internally consistent in terms of the overall tone and writing style.

Consistency Rating: 5 out of 5

Q: The text is easily and readily divisible into smaller reading sections that can be assigned at different points within the course (i.e., enormous blocks of text without subheadings should be avoided). The text should not be overly self-referential, and should be easily reorganized and realigned with various subunits of a course without presenting much disruption to the reader.

The content is chunked into quite small sections that appear easy to rearrange or otherwise modify.

Modularity Rating: 5 out of 5

Q: The topics in the text are presented in a logical, clear fashion

I don't have much to say here other than "yes".

Organization Rating: 5 out of 5

Q: The text is free of significant interface issues, including navigation problems, distortion of images/charts, and any other display features that may distract or confuse the reader

The web version seems fine no this front, however, the print version has some serious problems with readability.

Distracting/disruptive background: Figures 1.4.1 (also difficult to read with low tonal contrast between some of the text and their background - text should be black), 3.4.2

Line breaks in odd places, leaving a large blank white space at the end of a line: p.15 "noticed that one of the ... plates was contaminated", p16 "may be used to test a ... hypothesis"; p.212 "passive transport - which requires ... no energy expenditure", p.219 "Active transport may also ... require proteins called pumps"; Figure 16.2.4 has text wrapped around, leaving orphaned line "feces by the large intestine" under diagram rather than beside with the rest of its paragraph; section 17.4 "innate Immune Evasion" list has inappropriate line breaks at the od 2nd and 3rd points

Odd indent of orphan line at top of p.221 ("concentration gradient.")

Page breaks in unfortunate places, sometimes separating title from text or diagram caption from figure: p. 56-57 "Watch this TED-Ed video..." video on next page; p.62 "Linnaean Classification" section page cuts off mid-word "...grouping together organisms that s" to "hared obvious morphological..."; section 3.10 p.144 entirely blank page in the middle of attribution list; section 3.13 p.168 entirely blank page within attribution list; section 4.5 p.201 unnecessary page break midway through attributions list; Section 6.4 "Types of Responses" numbered list has the fourth item appear alone on subsequent page; section 8.8 attributions list split inappropriately (p.682 has a single line of text on it); end of section 9.5 has multiple excess page breaks; book break splits the Skeletal System chapter; Figure 12.2.2 caption separated from image; orphaned title "Structure of Blood Vessels" leaves a large blank space on p.1075

Images smaller than necessary: Figure 1.7.6 (relevance of that figure also not adequately explained/referenced in text); Tissue diagrams in Table 7.4.2 (whose caption also appears on the page before the figure) are considerably out of scale with the Histological sample images in the same table

Images larger than necessary: Figure 8.8.3 has minimal relevance to begin with, should not take up 1/2 a page in print; Figure 8.9.2; Figures 13.2.3-13.2.4 too wide for page; Figure 14.2.8 poorly cropped at bottom of image

Poor-quality, low-resolution images: Figures 2.2.2, 2.5.2 (illegible text), 3.2.3, 3.3.3, 3.5.3 (that one is OK but could be better), 3.6.2, 3.7.2, 312.2 (low-quality text within images general problem throughout), 5.10.6, 5.11.2, 5.16.2, 7.2.4, 7.5.2, 7.6.2, 8.7.9, 9.5.3, 11.3.2, 11.3.9, 11.5.2, 15.2.5, 17.6.3, 18.5.6, 18.6.3, 18.8.3

Images very dark in print: Figures 3.3.6, 3.7.3

Figure 14.4.4 is not helpful without a direct link to animation in text; no labels to show where the valve is

Poor diagram positioning on page: "Mitosis" steps split phases across pages rather than include all of one phase on one page (would fit if the whole-cycle images were made slightly smaller or omitted entirely as redundant); Figure 9.6.5 seems to have "no go" symbols placed off to the side and thus are unclear

Poor caption positioning, overlaps with colour blocks of section headings: Figures 4.6.6, 5.9.4, 9.2.3

Inconsistent font size: p.51 interactive/media element after "Reproduction" paragraph, Table 5.11.1 appears HUGE in print; Captions in Figures 7.4.4-7.4.7 very strangely formatted, seem to be squished into very narrow columns that split words

Inconsistent text formatting: p. 56 bulleted list 3/4 bolded; p58 "Feature: Myth vs. Reality" inconsistent with other chapters (these tables are inconsistently formatted between chapters in multiple places); Chapter 2.4 headings inconsistent with other chapters; yellow highlighting in attribution list of section 5.8; some Feature: Myth vs. Reality" tables p.466, 775, 888 very difficult to read/parse as large blocks of italicized or bolded text (formatting as in section 11.5 amd 13.3 is more legible); p.476 "High Altitude Adaptations in Andean Highlands" heading format inconsistent with other headings; section 11.6 "Feature: My Human Body" list has partially-bolded phrases (either bold each intro phrase, or don't); headings section 16.2 "Excretion" and "Excretory Organs" not bolded like others;

Unnecessary "cK-12" colour logo present in some attributions but not others.

Interface Rating: 4 out of 5

Q: The text contains no grammatical errors

Generally fine, spotted a small number that have been noted elsewhere in this review.
Section 2.3 "Oxygen makes up to 21 per cent of the atmosphere" should be presented as 21%, twenty-one percent, or 21 percent.

Grammar Rating: 4 out of 5

Q: The text is not culturally insensitive or offensive in any way. It should make use of examples that are inclusive of a variety of races, ethnicities, and backgrounds

It appears an effort has bene made to include diverse examples in the text and diagrams. I did not note ay insensitive or offensive language.

Cultural Relevance Rating: 5 out of 5

Q: Are there any other comments you would like to make about this book, for example, its appropriateness in a Canadian context or specific updates you think need to be made?

I would be hesitant to recommend this book for unadapted use, as it includes a lot of content that would not be considered testable in an introductory course. I would, however, recommend it for instructors willing to remove extraneous content for their students, especially for students wanting a print version.